Summary and result
If you run a project-based field services business, you pay for time entries twice. Staff type them in, and then someone checks them before the invoice can go out. This case study shows how time entry audit automation took the second payment out of the process at a project-based inspection and testing firm, and how invoice drafts followed.
In the 30 days from 7 October to 5 November 2026, the system audited 3,376 time entries automatically. Another 47 audit runs ended in an error, which is an error rate of about 1.3 percent. The same system created 138 invoice drafts and dispatched 335 invoices, and it recorded the sent date each time. On the modeled basis explained at the end of this article, that is about 221 hours of handling time across the two processes.
- Time entries audited
- 3,376 time entries audited
- Measured, 7 Oct to 5 Nov 2026
- Invoice drafts created
- 138 invoice drafts created
- Measured, same 30 days
- Invoices dispatched
- 335 invoice dispatches
- Measured, same 30 days
- Audit error rate
- 1.3 percent of audit runs failed
- About 1.3 percent: 47 failed of 3,423 audit runs
The process before
The firm sells inspection, sampling and testing work by the project. Every hour a field technician spends on a site becomes a time entry on a project, and every receipt for a hotel, a lab or a courier becomes a billable expense. Nothing is invoiced until those entries are right.
Three things made this slow and fragile before automation:
- A senior project manager checked time entries by hand. When a mistake turned up, the fix meant deleting the line and entering it again.
- Changing a project’s rate schedule meant every linked time entry had to be recalculated, and any entry that no longer matched had to be found and corrected.
- Receipts sat in shared folders until an administrator pulled them into the project as billable expenses.
At the end of that chain sat the invoicing process. The client described five manual steps for each invoice: audit project time and expenses, build the draft in the accounting system, customize the layout, send it and record the sent date, then reconcile the payment. On the minutes the client gave us, that is about 55 minutes of handling per invoice, spread over three roles. The per-step counts of 36 cases for the manual steps come from the client’s own description of how the work runs. The run counts for the automated steps come from the 30 day logs, so the two cover different periods.
- 1
Audit project time and expenses
Manual Senior project manager. 36 runs, 15 min each.
Then Create the invoice draft: 36 cases
- 2
Create the invoice draft
Manual Invoicing specialist. 138 runs, 10 min each.
Then Customize layout and apply overrides: 36 cases
- 3
Customize layout and apply overrides
Manual Invoicing specialist. 36 runs, 15 min each.
Then Dispatch invoice and record sent date: 36 cases
- 4
Dispatch invoice and record sent date
Manual Invoicing specialist. 335 runs, 5 min each.
Then Reconcile payment and post to the accounting system: 36 cases
- 5
Reconcile payment and post to the accounting system
Manual Accounting lead. 36 runs, 10 min each.
The numbers behind this figure
| Step | Who | Work | Runs | Median minutes | Goes to |
|---|---|---|---|---|---|
| Audit project time and expenses | Senior project manager | Manual | 36 | 15 | Create the invoice draft (36 cases) |
| Create the invoice draft | Invoicing specialist | Manual | 138 | 10 | Customize layout and apply overrides (36 cases) |
| Customize layout and apply overrides | Invoicing specialist | Manual | 36 | 15 | Dispatch invoice and record sent date (36 cases) |
| Dispatch invoice and record sent date | Invoicing specialist | Manual | 335 | 5 | Reconcile payment and post to the accounting system (36 cases) |
| Reconcile payment and post to the accounting system | Accounting lead | Manual | 36 | 10 | End |
What we built
We did not replace the finance team. We removed the keystrokes that did not need judgment and left a person on the steps that do. Six automations run on events from the project management platform. Each one is logged, so every run has a status.
How the time entry audit automation works
The audit step runs on every new time entry, triggered by the entry itself. A run takes seconds, and every run is logged with a status, which is how we know the success and error counts in this article. It does the approve step that the senior project manager used to do line by line.
That is the core of the time entry audit automation. A second automation handles rate schedules. When a project’s schedule changes, it relinks and recalculates the linked entries, so the change is made once instead of entry by entry.
Expense intake and invoice drafts
Two small automations support the expense receipt step, one that replaces part of the manual work and one that assists it. Once the time and the expenses are approved, another automation creates the invoice draft in the accounting system from the project data. The last one dispatches the invoice and records the sent date on the project, so the project record shows when each invoice went out.
This is the pattern we use for project invoicing automation in general, and for field services billing automation specifically: the system does the repeatable work, and it leaves a trail you can read. If you want the longer argument for why this approach holds up in production, read why most AI pilots never reach production.
The process after
After the build, the two steps that used to cost the most keystrokes, the draft and the dispatch, run on their own. Measured from process events, the draft takes about 0.3 minutes and the dispatch about 0.1 minutes. The three judgment steps are still manual, so the chain does not collapse to zero.
- 1
Audit project time and expenses
Manual Senior project manager. 36 runs, 15 min each.
Then Create the invoice draft: 36 cases
- 2
Create the invoice draft
Automated Invoicing specialist. 138 runs, 0.3 min each.
Then Customize layout and apply overrides: 36 cases
- 3
Customize layout and apply overrides
Manual Invoicing specialist. 36 runs, 15 min each.
Then Dispatch invoice and record sent date: 36 cases
- 4
Dispatch invoice and record sent date
Automated Invoicing specialist. 335 runs, 0.1 min each.
Then Reconcile payment and post to the accounting system: 36 cases
- 5
Reconcile payment and post to the accounting system
Manual Accounting lead. 36 runs, 10 min each.
The numbers behind this figure
| Step | Who | Work | Runs | Median minutes | Goes to |
|---|---|---|---|---|---|
| Audit project time and expenses | Senior project manager | Manual | 36 | 15 | Create the invoice draft (36 cases) |
| Create the invoice draft | Invoicing specialist | Automated | 138 | 0.3 | Customize layout and apply overrides (36 cases) |
| Customize layout and apply overrides | Invoicing specialist | Manual | 36 | 15 | Dispatch invoice and record sent date (36 cases) |
| Dispatch invoice and record sent date | Invoicing specialist | Automated | 335 | 0.1 | Reconcile payment and post to the accounting system (36 cases) |
| Reconcile payment and post to the accounting system | Accounting lead | Manual | 36 | 10 | End |
The honest reading of this map is modest. On a single invoice the saving is about 15 minutes, and 40 minutes of work remain. The larger gain is volume: the audit step runs thousands of times a month, and each run that no longer needs a person adds up.
Result in numbers
The audit step carries the result. Time entry audit automation accounts for about 112 of the 221 modeled hours, more than the next two automations combined. Expense intake is second, which is typical for field businesses where receipts arrive in small, frequent batches.
manual automated
The numbers behind this figure
| Automation | Work | Modeled hours saved |
|---|---|---|
| Time entry audit and approval | automated | 112.5 |
| Expense receipts, assisted step | automated | 35.8 |
| Invoice dispatch and sent date | automated | 27.9 |
| Invoice draft creation | automated | 23 |
| Expense receipts, replaced step | automated | 15.4 |
| Rate schedule relink and recalculation | automated | 6.5 |
| Total | 221.1 |
Volume was not flat. The time and expense automations ran between 1,013 and 1,686 times per 7-day block, with the peak in the block starting 21 October. The invoicing automations ran between 98 and 142 times per block. Invoicing follows project billing cycles, so it moves in steps rather than in a trend. The last block covers only 2 days.
The numbers behind this figure
| 7-day block starting | Time and expense automation runs (runs) |
|---|---|
| 7 Oct | 1,173 |
| 14 Oct | 1,013 |
| 21 Oct | 1,686 |
| 28 Oct | 1,655 |
| 4 Nov (2 days) | 436 |
The numbers behind this figure
| 7-day block starting | Invoice draft and dispatch automation runs (runs) |
|---|---|
| 7 Oct | 111 |
| 14 Oct | 99 |
| 21 Oct | 142 |
| 28 Oct | 98 |
| 4 Nov (2 days) | 27 |
Where the errors were
The 47 failed audit runs were not spread evenly. 39 of them fell on three days, 24 October, 26 October and 2 November, when between about 7 and 19 percent of that day’s runs failed. A cluster like that points to specific causes, not constant background noise. It is also a reason to keep automation under supervision: the error count is visible only because every run is logged.
The other automations were steadier. Rate schedule relinking failed on 3 of 82 runs, dispatch on 4 of 339, and invoice drafts on none of 138. That field services billing automation had zero failed drafts in the window is useful, but it is a small sample of 138, so treat it as a good month, not a guarantee.
What we left manual
Three steps in the invoicing process are still done by people, and that is deliberate.
- Audit project time and expenses. About 15 minutes, senior project manager. The client told us that when a mistake turns up, the fix is to delete the line and enter it again, and that judgment stays with a person.
- Customize layout and apply overrides. About 15 minutes, invoicing specialist. Clients ask for different layouts: line by line, grouped by activity or a single lump sum, with labor and expenses subtotaled separately. We chose not to automate the judgment about what each client expects.
- Reconcile payment and post to the accounting system. About 10 minutes, accounting lead. This is where money meets the books. We would rather a person confirm it.
Be clear about what these numbers are. The minutes for these three steps come from the client, who described 36 cases. We did not time them. We also do not know how often these steps run in a given month, so this article does not turn them into a monthly cost.
Leaving steps manual keeps the project manager and the accounting lead in control of the parts that carry risk. If you are weighing a similar build, our view is that a good automation shortens the manual part of the chain and does not hide it. The same thinking sits behind how we count hours saved across client automations.
How we calculated this
Every number in this article comes from the run logs of the automations and from the process model of the two processes. Counts are measured. Hours and dollars are modeled.
- Window: 30 days, 7 October to 5 November 2026, counted by day. Run counts for that window are 3,423 audit runs (3,376 successful), 2,149 and 309 expense runs, 82 relink runs (79 successful), 138 draft runs and 339 dispatch runs (335 successful).
- Minutes saved per run: 2 for the audit, 1 and 3 for the two expense automations, 5 for relinking, 10 for the invoice draft and 5 for dispatch. These are default model settings that we have not replaced with stopwatch timings.
- Where figures conflicted, we used the lower one. The monitoring tool defaults to 15 minutes for the invoice draft while the client stated 10 for that step, so we used 10. It values the audit at 30 USD an hour while the role it replaces is priced at 65, so we used 30.
- Rates: 30 USD for the audit, 45 for expenses, 65 for relinking and 40 for invoicing.
- Total: about 221 hours and about 8,100 USD of modeled handling time across the two processes. That is the value of time at those rates, not money the client saved or banked.
- What we did not use: the process model for time and expense tracking reads a sample of events, so we quote its run counts from the run logs and not its cost totals. The repeated events the map shows for dispatch and draft are repeated runs on one case, not rework, so we do not count them as delay.
Company name, stack and the numbers behind this are shared on the audit call.
