How to Increase Billable Hours in a Heavy-Duty Repair Shop

How to Increase Billable Hours in a Heavy-Duty Repair Shop

A heavy-duty repair shop can be busy all day and still leave money on the table.

The bays may be full. Technicians may be working. Trucks may be waiting outside. The phone may not stop ringing.

But if labor is not tracked, reviewed, approved, and invoiced correctly, the shop can lose billable hours without realizing it.

That is why increasing billable hours is not just about asking technicians to work faster.

In most diesel, truck, and fleet repair shops, lost billable labor comes from workflow gaps:

• technician time is entered late

• labor is not tied to the work order

• diagnostic time is underbilled

• parts delays are not tracked

• approvals are slow

• notes are too vague to support billing

• invoices are created after key details are forgotten

• actual time is not compared against billed time

The goal is not to overbill customers.

The goal is to stop underbilling work your shop already performed.

With labor rates rising and many shops still struggling to hire technicians, the easiest revenue gain is often not adding more people. It is capturing more of the labor already happening inside the shop. Industry reporting showed a median shop labor rate of $149/hour, up 7.4% from 2024, and reported that 57% of shops are currently understaffed.

That means every missed billable hour matters more than ever.

This guide breaks down how heavy-duty repair shops can increase billable hours by improving labor tracking, work order discipline, technician productivity, parts flow, approvals, and invoicing.

What Are Billable Hours in a Heavy-Duty Repair Shop?

Billable hours are the labor hours your shop charges to a customer, fleet account, warranty provider, or internal account for approved work.

In a heavy-duty repair shop, billable labor may include:

• diagnostics

• inspections

• preventive maintenance

• brake repair

• suspension work

• aftertreatment diagnostics

• electrical troubleshooting

• engine repair

• trailer repair

• DOT-related repairs

• mobile service labor

• road testing

• teardown and inspection

• approved reassembly

• final verification

But not every technician hour becomes billable.

A technician may also spend time:

• waiting on parts

• waiting on customer approval

• waiting on fleet authorization

• moving trucks

• searching for tools

• helping another technician

• correcting missing work order information

• cleaning the bay

• dealing with rework

• documenting warranty details

• handling internal tasks

Some of that time is necessary. Some of it is preventable. Some of it should be billable if documented and approved properly. Some of it should not be billed but still needs to be tracked.

That is why heavy-duty shops need to separate five types of labor time:

Most shops do not need more complexity.

They need better visibility.

If you cannot see the difference between clocked hours, job hours, billed hours, and missed labor, you cannot reliably increase billable hours.

Why Heavy-Duty Shops Lose Billable Hours

Heavy-duty shops rarely lose billable hours in one obvious place.

They lose them in small leaks across the day.

A technician forgets 20 minutes of diagnostic time. A service advisor leaves a labor line off the invoice. A truck sits half a day waiting on parts. A job goes over estimate, but no one gets additional approval. A completed repair order waits two days before invoicing. Notes are too vague, so labor gets reduced to avoid a customer dispute.

Individually, those leaks may seem small.

Across multiple technicians, bays, and work orders, they become serious revenue loss.

Here are the most common places billable hours disappear.

1. Technician Time Is Not Attached to the Work Order

The biggest problem is not always that time is missing.

Sometimes time exists, but it is not connected to the right job.

For example, a technician may write down that they worked 6.5 hours that day. But if that time is not tied to specific work orders, labor lines, units, or repair tasks, the office team has to reconstruct the story later.

That creates risk.

The service advisor has to figure out:

• which technician worked on which job

• how long each task took

• what was diagnostic time

• what was repair labor

• what was waiting time

• what was approved

• what should be billed

• what was already included in the estimate

When time tracking and work orders live in separate places, labor gets missed.

To increase billable hours, technician time should be attached directly to:

• the work order

• the unit or asset

• the labor line

• the technician

• the start and stop time

• the billable or non-billable status

• supporting notes

A shop cannot consistently bill what it cannot clearly connect to the job.

2. Diagnostics Are Underbilled

Diagnostic labor is one of the easiest places to lose money in a diesel repair shop.

Heavy-duty diagnostics can take real time.

Electrical faults, aftertreatment problems, air leaks, intermittent issues, communication faults, hydraulic problems, and engine performance complaints are not always simple. A technician may need to inspect, test, scan, road test, isolate, retest, and verify.

But many shops still treat diagnostics like a small add-on.

That creates a billing problem.

If a technician spends 1.5 hours diagnosing an issue, but the invoice only shows the final repair, the shop loses revenue and the customer does not see the full value of the work.

A better process is to treat diagnostics as its own workflow.

Examples of diagnostic labor lines include:

• initial diagnostic inspection

• electrical diagnostics

• aftertreatment diagnostics

• fault code testing

• air system diagnostics

• hydraulic diagnostics

• teardown for diagnosis

• road test and verification

• additional diagnostic time after approval

The key is approval.

A shop can start with an initial diagnostic authorization, then request approval for additional diagnostic time if the issue requires more work.

This protects the customer and the shop.

It also helps technicians feel that their problem-solving time is being recognized instead of disappearing into the repair.

3. Estimates Are Not Compared Against Actual Time

Many shops estimate work, complete the repair, and invoice the customer without reviewing how the estimate compared to actual labor.

That is a major missed opportunity.

If a job was estimated at 3.0 hours and took 5.2 hours, the shop needs to understand why.

Maybe the estimate was too low. Maybe the truck had corrosion or previous poor repairs. Maybe the technician had to wait for a part. Maybe the customer approved extra work, but the additional labor was never added. Maybe the standard labor time no longer matches the reality of that job type.

Without actual-vs-estimated review, the shop keeps guessing.

To increase billable hours, review labor variance before the invoice goes out.

Ask:

• What was estimated?

• What actually happened?

• Was the extra time approved?

• Was the labor documented?

• Was the invoice updated?

• Should future estimates change?

This is where standard repair times matter.

The Technology & Maintenance Council’s SRT survey is designed to help establish baseline repair times that improve shop productivity and profitability, and it uses VMRS-based labor descriptions and component codes to aggregate repair tasks.

For heavy-duty shops, SRTs should not be treated as perfect numbers. They should be used as baselines.

The best shops compare:

• standard repair time

• estimate

• actual technician time

• billed labor

• reason for variance

That is how they find underbilling, poor estimating, workflow delays, and training opportunities.

4. Parts Delays Block Billable Capacity

Technicians cannot produce billable labor while waiting on parts.

Some parts delays are unavoidable. But many shops lose more time than they realize because parts are not staged, inventory is inaccurate, common parts are missing, or parts are not tied clearly to the work order.

Parts delays reduce billable hours in several ways:

• technicians stop active work

• trucks occupy bays while waiting

• jobs get interrupted and restarted

• service advisors lose momentum

• invoices get delayed

• technicians switch between jobs inefficiently

• customers wait longer for completion

The problem is not just inventory.

It is workflow.

A shop should track when a repair order is delayed because of parts. If parts delays are not coded, they become invisible. The technician may look inefficient even though the real issue is parts availability.

Useful parts-related delay codes include:

• waiting on parts

• part ordered

• part backordered

• wrong part received

• part not staged

• vendor delay

• sublet delay

• warranty part approval pending

Once parts delays are visible, managers can fix the right issue.

For example:

• stock more fast-moving parts

• pre-stage parts for scheduled PMs

• verify parts before assigning the job

• improve purchase order review

• cycle-count common items more often

• track vendor performance

• separate “waiting on parts” from active repair time

Increasing billable hours is not only about technician speed.

It is also about removing the blockers that prevent technicians from producing billable work.

5. Customer and Fleet Approvals Are Too Slow

Approval delays are another major source of lost billable capacity.

A technician diagnoses a problem. The repair requires customer approval. The advisor sends the estimate. The truck sits. The bay stays occupied. The technician moves to another job. Hours later, the customer approves the work, but now the technician has to restart the job.

That delay may not be billable, but it still costs the shop.

In heavy-duty repair, approval delays are common because many jobs involve:

• fleet managers

• maintenance coordinators

• owner-operators

• warranty providers

• internal approvals

• large repair estimates

• multiple units

• after-hours authorization

To increase billable hours, shops need a faster approval workflow.

That means:

• clear estimates

• strong technician notes

• photos when useful

• diagnostic findings explained clearly

• approved labor separated from recommended labor

• response deadlines when possible

• repair status visibility

• follow-up reminders

Approval delays should also be tracked.

A simple delay code like WAIT_AUTH helps the manager see how much shop capacity is being lost to approvals.

If a shop loses 20 hours a week to approval delays, the solution is not to tell technicians to work harder. The solution is to improve the approval process.

6. Technician Notes Are Too Weak to Support Billing

Weak notes lead to weak invoices.

If a technician writes “fixed issue,” the advisor has very little to work with. The customer may question the labor. The advisor may reduce the charge. The invoice may not fully reflect the work performed.

A stronger note tells the labor story.

Weak note:

Fixed air leak.

Better note:

Inspected air system, found leak at fitting near rear service tank, removed damaged fitting, installed replacement fitting, pressure-tested system, and verified pressure held after repair.

That second note supports the labor.

It shows:

• what was inspected

• what was found

• what was repaired

• what was verified

Technician documentation does not need to be long. It needs to be useful.

A simple note structure works well:

1. Customer concern

2. Inspection performed

3. Cause found

4. Repair completed

5. Test or verification performed

Good notes help the advisor bill confidently.

They also help with fleet history, warranty questions, repeat repairs, customer communication, and future estimates.

7. Invoices Are Created Too Late

The longer a shop waits to invoice, the more labor details disappear.

Technicians move on. Advisors forget context. Parts need to be checked again. Notes become harder to interpret. Customers ask questions after the job is no longer fresh.

Delayed invoicing creates billing leakage.

It also slows cash flow.

To increase billable hours, shops should review labor before the invoice goes out, ideally the same day the work is completed.

Before closing a work order, review:

• technician time

• billed labor

• diagnostic time

• parts used

• customer approvals

• additional work

• delay reasons

• technician notes

• estimate variance

• final verification

Do not let labor disappear between the bay and the invoice.

8. The Shop Is Busy, But Not Productive

A full shop can be misleading.

A bay with a truck in it is not always a productive bay.

The truck may be waiting on parts. Waiting on approval. Waiting for another technician. Waiting for sublet work. Waiting for notes. Waiting to be invoiced.

From the outside, the shop looks busy.

But the shop may not be generating enough billable labor.

That is why managers need to separate:

• active repair time

• waiting time

• completed but uninvoiced work

• non-billable admin time

• bay occupancy

• billable labor captured

A shop can be packed and still underperform.

Increasing billable hours requires knowing which jobs are actually moving and which jobs are just taking up space.

How to Increase Billable Hours Without Adding Technicians

The most practical way to increase billable hours is to recover labor already being lost.

Here is the process.

Step 1: Track Time by Work Order and Labor Line

Clocking in for the day is not enough.

A technician may work eight hours, but the shop needs to know how those hours were used.

Track technician time by:

• work order

• labor line

• technician

• job type

• start time

• stop time

• billable status

• delay reason if work stops

Example:

This makes it easier to see where labor is being captured and where it is leaking.

If diagnostics consistently show 1.4 actual hours but only 1.0 billed hour, that is a pattern worth fixing.

Step 2: Separate Billable and Non-Billable Time

Do not hide non-billable time.

Track it.

Non-billable time helps identify workflow problems.

Examples:

If non-billable time is not tracked, managers may blame technicians for problems caused by workflow.

A technician cannot bill hours while waiting on parts, waiting on authorization, or searching for missing information.

Step 3: Use Delay Codes

Delay codes turn vague downtime into usable data.

Start simple.

Use a small set of codes that everyone understands:

This gives the shop visibility.

If WAIT_PARTS is the biggest delay code, fix parts flow. If WAIT_AUTH is the biggest delay code, fix approvals. If REWORK_INTERNAL is high, look at quality control or training.

Without delay codes, every lost hour looks the same.

With delay codes, the shop knows what to fix.

Step 4: Build Standard Repair Time Baselines

Heavy-duty shops should use standard repair times carefully.

Unlike some automotive jobs, heavy-duty repairs often vary by vehicle class, equipment type, condition, configuration, corrosion, access, fleet spec, and component type.

That does not mean SRTs are useless.

It means they should be used as baselines, not blind rules.

TMC’s 2025 SRT survey covers 103 commonly performed labor tasks and is designed to help establish baseline repair times that improve shop productivity and profitability. The survey is VMRS-based and asks participants for actual time in hours to install parts or perform labor in their facilities.

A practical shop-level process looks like this:

1. Start with available labor guides or SRT references.

2. Track actual time by job type.

3. Compare actual time against estimated time.

4. Review outliers.

5. Adjust estimating rules.

6. Train advisors and technicians on common variance causes.

7. Review monthly.

Example:

This helps the shop stop guessing.

It also prevents the same underbilling mistake from happening repeatedly.

Step 5: Review Actual Time vs. Billed Time Every Day

This is one of the highest-impact habits.

Every day, review completed or nearly completed work orders and ask:

• How much actual time was logged?

• How much labor is being billed?

• Is there a gap?

• Is the gap intentional?

• Was extra labor approved?

• Are notes strong enough?

• Are diagnostics fully captured?

• Are parts and sublet items attached?

• Is the invoice ready?

A simple daily review can recover missed labor before the invoice goes out.

Example:

This does not mean every gap is bad.

Sometimes a shop intentionally writes off time. Sometimes a job is billed by flat rate. Sometimes goodwill adjustments are strategic.

The important thing is that the decision is visible and intentional.

Step 6: Improve Diagnostic Approval Workflows

Diagnostics should not be vague.

A better process is to sell diagnostics in stages.

For example:

Stage 1: Initial diagnostic authorization
Customer approves up to 1.0 hour of diagnostic time.

Stage 2: Additional diagnostic request
If the technician cannot confirm the root cause within the first approved block, the advisor contacts the customer with findings and requests approval for additional diagnostic time.

Stage 3: Repair estimate
Once the cause is found, the shop presents the repair estimate with labor, parts, and timeline.

This protects everyone.

The customer knows what they approved. The technician has time to diagnose properly. The advisor has documentation. The shop captures diagnostic labor instead of burying it.

A simple advisor script:

“We completed the first diagnostic block and confirmed the issue is deeper than the initial fault code. The technician needs additional testing to isolate the root cause before we recommend parts. We’re requesting approval for one additional hour of diagnostic time.”

This is much better than doing the work and hoping to bill it later.

Step 7: Reduce Waiting Time

Increasing billable hours is not only about billing more.

It is also about creating more billable capacity.

Every hour a technician spends waiting is an hour they are not producing billable labor.

Start by identifying the top two causes of waiting time in your shop.

Common blockers:

• parts not available

• parts not staged

• customer approval delays

• unclear work instructions

• missing diagnostic information

• poor scheduling

• unavailable tools

• bay congestion

• sublet delays

• warranty authorization

• incomplete estimates

Then fix the biggest blocker first.

For many heavy-duty shops, the biggest opportunities are:

• faster approval communication

• better parts staging

• clearer work order assignments

• technician time tracking

• same-day labor review

• more accurate estimates

Small workflow fixes can create large revenue gains.

For example, recovering just 30 minutes of billable labor per technician per day can add meaningful revenue over time, especially at modern heavy-duty labor rates.

Step 8: Tighten Parts Flow

Parts flow has a direct impact on billable hours.

If parts are not ready, technicians stop producing.

A stronger parts workflow includes:

• pre-staging parts for scheduled work

• tying parts to the correct work order

• verifying parts before assigning the technician

• tracking parts-related delays

• cycle-counting fast-moving inventory

• reviewing vendor performance

• separating ordered, received, staged, and installed parts statuses

For repeat jobs like PMs, brake work, filters, lighting, common air system repairs, and suspension items, parts kits can reduce downtime.

The goal is simple:

Technicians should spend more time repairing and less time waiting, searching, or walking.

Step 9: Improve Work Order Quality

A work order should tell the story of the job.

Weak work orders create billing problems.

A strong work order should include:

• customer concern

• unit information

• assigned technician

• approved labor

• diagnostic findings

• parts used

• labor lines

• technician notes

• delay reasons

• approvals

• final verification

• invoice-ready summary

If the work order is incomplete, the invoice will be incomplete.

That is why work order discipline directly affects billable hours.

A good rule:

If the labor is not clear on the work order, it is at risk of not being billed.

Step 10: Create a Daily Billable Hours Scorecard

You do not need 50 reports.

Start with a simple scorecard.

Track these metrics daily or weekly:

The goal is not to micromanage every minute.

The goal is to spot patterns.

If billed-hour efficiency is low, find out why. If parts-delay hours are high, fix parts. If diagnostic recovery is low, fix approvals. If same-day invoice close rate is low, fix work order review.

Step 11: Do Not Sacrifice Safety or Quality

Increasing billable hours should never mean rushing unsafe work.

Heavy-duty repair involves real risks: lifts, heavy parts, chemicals, electrical systems, air systems, hot components, rotating equipment, and large vehicles.

OSHA notes that vehicle maintenance workers face hazards from chemicals, noise, equipment, and other shop conditions, so productivity improvements should be built around better systems, not unsafe shortcuts.

The best shops increase billable hours by:

• reducing waiting time

• improving documentation

• capturing diagnostic labor

• fixing parts flow

• using better scheduling

• reviewing labor before invoicing

• tracking delays

• reducing rework

Not by pressuring technicians to cut corners.

A quality-adjusted productivity mindset matters.

Track billable hours, but also track:

• comebacks

• rework

• safety incidents

• customer disputes

• warranty claims

• missed inspections

More billed hours only help if the work is done correctly.

Step 12: Use Software When Manual Tracking Stops Working

Spreadsheets and paper can work for a very small shop.

But once a shop has multiple technicians, multiple bays, fleet customers, parts delays, mobile work, sublets, and multi-day jobs, manual systems start breaking down.

Signs your shop has outgrown manual tracking:

• technicians enter time late

• labor is missing from invoices

• advisors chase updates

• work orders and time logs do not match

• managers cannot see active jobs

• estimates are not compared against actual time

• approvals are delayed

• parts delays are not tracked

• completed jobs wait too long to invoice

• reports are built manually

• the shop is busy but revenue does not match the workload

At that point, the issue is not just time tracking.

The issue is disconnected workflow.

Heavy-duty shop management software can help connect:

• technician time

• work orders

• labor lines

• parts

• scheduling

• approvals

• notes

• invoices

• reporting

This makes it easier to see which jobs are active, which are waiting, which labor has been captured, and which work orders are ready to invoice.

The software does not create billable hours by itself.

But it helps the shop stop losing them.

A 30-Day Plan to Recover More Billable Labor

Here is a practical 30-day plan a heavy-duty repair shop can start using immediately.

Week 1: Measure the leak

Track:

• clocked technician hours

• active job hours

• billed labor hours

• completed but uninvoiced jobs

• diagnostic hours worked

• diagnostic hours billed

Goal:

Find the gap between hours worked and hours billed.

Week 2: Add delay codes

Start with five codes:

• WAIT_PARTS

• WAIT_AUTH

• DIAG_ADDL

• BAY_BLOCKED

• REWORK_INTERNAL

Goal:

Understand why work stops.

Week 3: Review labor before invoicing

Before any invoice goes out, check:

• actual time vs billed time

• notes

• approvals

• diagnostic labor

• parts

• delays

• estimate variance

Goal:

Catch missed labor before the invoice is sent.

Week 4: Fix the biggest bottleneck

Pick the biggest source of lost time.

It may be:

• diagnostics

• parts delays

• approvals

• weak notes

• slow invoicing

• poor scheduling

Fix one major bottleneck before adding more complexity.

Goal:

Recover more billable labor without adding headcount.

Example: How Small Labor Leaks Add Up

Let’s say a shop has five technicians.

Each technician misses only 20 minutes of billable labor per day because of late time entry, weak notes, or missed diagnostic time.

That is:

• 100 minutes per day

• 500 minutes per week

• 8.3 hours per week

At a $149/hour labor rate, that is more than $1,200 per week in potential labor leakage.

Over a year, that can become more than $60,000 in missed labor revenue.

And that is from only 20 minutes per technician per day.

The exact numbers will vary by shop, but the principle is simple:

Small labor leaks become large revenue leaks.

Common Mistakes That Reduce Billable Hours

Mistake 1: Only tracking clock-in and clock-out time

Attendance time is useful for payroll, but it does not show whether labor was tied to repair orders or billed properly.

Mistake 2: Not billing diagnostics correctly

Diagnostic work is real labor. If it is approved and documented, it should not disappear.

Mistake 3: Treating all lost time as technician inefficiency

Waiting on parts, approvals, vendors, and bays are workflow problems, not always technician problems.

Mistake 4: Letting weak notes drive billing decisions

If the labor story is unclear, the invoice usually gets weaker.

Mistake 5: Reviewing labor after the invoice is already sent

By then, it is usually too late.

Mistake 6: Using generic labor times without shop actuals

Standard repair times are useful baselines, but each shop should compare them against its own actuals.

Mistake 7: Pushing speed without protecting quality

More billable hours should come from better workflow, not unsafe shortcuts or rushed repairs.

Final Thoughts

Increasing billable hours in a heavy-duty repair shop does not mean squeezing technicians harder.

It means capturing the work your shop already performs.

Most shops lose billable hours because their workflow has gaps. Technician time is entered late. Work orders are incomplete. Diagnostics are underbilled. Parts delays are invisible. Approvals take too long. Actual time is not compared against billed labor. Invoices are created after details are forgotten.

The fix is a better system.

Track time by work order. Separate billable and non-billable labor. Use delay codes. Review actual time before invoicing. Improve technician notes. Build standard repair time baselines. Reduce parts and approval delays. Monitor the right KPIs.

When those habits are in place, a shop can increase revenue without adding more technicians, more bays, or more chaos.

Want to capture more billable labor from every work order? ShopView helps heavy-duty repair shops track technician time, manage work orders, reduce paperwork, and turn completed work into accurate invoices faster. Schedule a demo today.

Frequently Asked Questions

How can a heavy-duty repair shop increase billable hours?

A heavy-duty repair shop can increase billable hours by tracking technician time by work order, reviewing actual time before invoicing, billing approved diagnostic labor properly, reducing parts and approval delays, and improving work order documentation.

What causes heavy-duty shops to lose billable labor?

Common causes include late time entry, labor not tied to work orders, underbilled diagnostics, weak technician notes, parts delays, slow approvals, incomplete estimates, and invoices created too long after the work is completed.

What is the difference between clocked hours and billable hours?

Clocked hours show how long a technician was on the clock. Billable hours show how much labor was charged to a customer, fleet, warranty provider, or internal account. A shop needs both numbers to understand productivity and revenue capture.

Should diagnostic time be billable?

Yes, diagnostic time should be billable when it is approved, documented, and part of the repair process. Many shops lose revenue because diagnostic labor is performed but not clearly added to the estimate or invoice.

How do standard repair times help increase billable hours?

Standard repair times help shops estimate labor more consistently, compare estimated time against actual time, identify recurring overruns, and reduce underbilling. Heavy-duty shops should use SRTs as baselines and compare them against their own shop data.

Why do spreadsheets make it harder to increase billable hours?

Spreadsheets are often updated after the work is done, separate from work orders, and difficult to maintain across multiple technicians, bays, parts delays, and fleet approvals. This makes it easier for labor to be missed before invoicing.

What KPIs should a shop track to improve billable hours?

Useful KPIs include billed-hour efficiency, wrench-time utilization, billable capture rate, actual vs estimated labor, diagnostic recovery rate, parts-delay hours per repair order, same-day invoice close rate, and rework rate.