Simpro for Contractor Billing: A ChatGPT Check Before Each Invoice

In Simpro Premium you bill a job in stages by raising a deposit invoice, then numbered progress claims, then a final claim, each from the job. Before each one goes out, give ChatGPT or Claude the quote scope and the invoice lines and ask it to list mismatches, then confirm every flag yourself in Simpro.

The check matters because a wrong claim is awkward to repair. Simpro's help says that changing a progress claim's total means deleting the invoice, and any others linked to that cost centre on the job, and starting again. Catch the error while the invoice is still Pending, before the customer has a copy and before it reaches your accounting package.

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How Simpro bills a staged job, in the order you raise things

The sequence below follows Simpro's Help Guide articles for Simpro Premium as they read on 1 November 2026. Button names are Simpro's; open the linked articles for the exact screens on your version.

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1. Deposit. On the job, choose Deposit as the invoice type and enter the amount as a percentage or a figure, or use Deposit All to invoice in full. Deposit amounts can be set at section or cost-centre level.
2. Progress claims. Claims are numbered in order: Progress Claim #1, #2 and so on. On a job that already has a claim, the help says to use Options, then Create Progress Claim. You can claim per item, or enter a claim amount as a percentage or a fixed figure at section or cost-centre level. Where a job has several cost centres, only those not completely claimed are shown, and the percentage claimed on each flows to the income account it is assigned to. Choose the method on claim #1: once you claim by value, Claim Per Item is no longer offered for later claims on that job.
3. Final claim. The last claim is labelled Final Claim, and Finalise Claim claims every cost centre still open.
4. Deposit credit. One method the guide describes invoices a positive deposit cost centre up front and claims a matching negative deposit cost centre on the final invoice, so the deposit comes off at the end.
5. Retention, where used. Retention is set up at the start of the project and deducted from each progress claim. The final claim releases the share your set-up calls the Final Claim Rebate, and when the retention period has passed since the Job Completed date, an alert appears in the System menu and you raise a retention claim for the rest. The help's own example holds 5%, releases 2% on the final claim and 3% on the retention claim. Walk Me Through, under Help, has a guided version.

Builds differ in vocabulary. Some say progress claim and retention, others progress invoice and retainage, and some say work order where others say job card. They are the same steps, so use whichever words your screens show.

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One trap: the Help Guide's Contractor Invoices article is not about billing your customer. In Simpro, contractors are the subcontractors you pay, and that article covers recording the invoices they send you so actual costs land on the job. Everything in this tutorial runs the other way: billing your customer.

One more tool is worth knowing if your customer signs off each claim before it is invoiced. Simpro's Request for Claim is almost identical to a progress claim but posts nothing to your accounting package, and once the customer approves it you convert it into a deposit or progress claim. The check below fits there too, before the request goes out, which means the customer never sees a draft with a double claim in it.

Use the Pending stage as your checkpoint

Simpro's help says invoices can be given two approval stages, Pending and Approved, which apply to deposits, requests for claim, progress claims and tax invoices. The stages are optional. Pending invoices have no effect on your accounting package, while approved ones go through on the next export. You can also restrict unapproved invoices so that only approved ones can be emailed to a customer, decide by security group who may approve, and set approval limits so a user can approve only invoices below a set value. That gives the check a natural home.

1. Raise the claim as Pending.
2. Copy the lines into the redaction template below and run the check.
3. Fix anything real in Simpro. If a total is wrong, remember the delete-and-redo rule, which costs less now than after sending.
4. Open the claim, release its lock, set Invoice Stage to Approved and click Finish.
5. Only then email it.

The restriction is the Restrict Unapproved Invoices check box, found under System, Setup, System Setup, Defaults, System, next to the default Invoice Stage. Without it, the help says invoices can be emailed before they are approved, so the Pending stage is a convention and not a control. Set the default stage to Pending, tick the box, and an employee without approval permission can no longer pick Approved or open the Forms tab to email the claim. Then split the roles: one person raises the claim, and a different person, or the owner, runs the check and approves it. A check run by the person who built the invoice catches fewer errors, because they read what they meant instead of what they typed.

What goes into the chat and what stays out

The check needs line descriptions, amounts, percentages and the scope paragraph from the quote. It does not need the customer's name, address, contact details, bank details or your job number. Swap those for neutral labels before pasting, and use a business plan whose data settings you have read.

Before (as it sits in Simpro):
Invoice to: [customer company], [site address]. Job 1042. Progress Claim #2.
Pay to: [bank details]

After (as it goes into the chat):
Invoice to: Customer A. Job A. Progress Claim #2.
(bank line removed)

Keep a one-line redaction habit and the rest is easy: names out, numbers and descriptions in. If the quote scope mentions a customer's trade secrets or security arrangements, summarise the scope in your own words rather than pasting it.

The scenario: a $48,600 install and its second claim

The running example is a small mechanical contractor installing air conditioning in an office. The job was quoted at $48,600 across four cost centres, a 20% deposit of $9,720 has been paid, and progress claim #1 has gone out. All figures here are illustrative.

Claim #1 took A at 100% ($4,200), B at 50% ($11,200) and C at 25% ($4,000), a total of $19,400. The office has now drafted claim #2 as a Pending invoice with these lines.

Three things are wrong with it, and none is obvious when you read the total. Line 1 claims a cost centre that claim #1 already took in full. Line 3's wording promises electrical isolators, which the quote excludes. Line 4 bills a variation with no approval reference. A tired reader sees a sensible sum and clicks Approved.

The check prompt, with a realistic reply and what to fix in it

Give the assistant three blocks of text: the quote scope and prices, what has already been claimed, and the draft lines. Then use a prompt that asks for flags, not totals.

You are checking a contractor's progress claim before it is sent. I will give you (1) the scope and prices from the original quote, (2) what has already been claimed, (3) the draft lines for this claim.
Do not recalculate the grand total. Instead:
A. Flag any cost centre where the cumulative percentage claimed would exceed 100%.
B. Flag any line whose description mentions work, materials or services the quote excludes or does not mention.
C. Flag any line with no matching cost centre and no variation reference.
D. Flag wording that could be read as a larger scope than the quote.
List each flag with the line number and the exact words that triggered it. If you are unsure, say so. Do not add tax, retention or fees I have not mentioned.

A realistic reply, trimmed (illustrative):

1. Line 1, cost centre A: cumulative claimed would be 200%. Claim #1 took 100% ($4,200) and this line claims 100% again.
2. Line 3, cost centre C: the description says "supply and installation of electrical isolators". The quote excludes electrical supply works and says connection is to isolators installed by others.
3. Line 4: no variation reference or approval date, and "extras" is not an item in the quote.
4. Lines 2 and 3: cumulative percentages are 100% and 60%, within limits.
5. Suggested correction: the corrected total is $17,950, plus tax at 10% and retention at 5%.

Now decide what to keep. Flags 1 to 3 are real, and each quotes the exact words that triggered it, which is what makes them checkable. Flag 4 is a useful confirmation and goes in your log. Item 5 is where the assistant went wrong in three ways. It added tax at a rate you never gave it, it deducted retention although this job has none, and its corrected total includes the unapproved variation. Ignore all three. You told it not to add them, and it did anyway, which is why you recompute the numbers yourself.

Recompute the numbers yourself in two minutes

The assistant's job ends at the flags. The sums are yours, done in Simpro or a spreadsheet, and the table below is the shape worth keeping. It shows the corrected claim #2 with line 1 removed and the variation held back until it has an approval.

The corrected claim is $16,800, not $22,150. Line 1 alone would have overbilled by $4,200, and the variation joins a later claim once it carries an approval reference. If nobody had read the draft closely, the customer's accounts team would have found the double claim, and a double claim on cost centre A is exactly the kind of thing that makes a customer re-read every later invoice with suspicion.

Wording checks: scope words that turn a claim into an argument

A second pass on the descriptions catches wording that promises more than the quote does. Run it as its own prompt, so the assistant is not splitting its attention between sums and phrases.

List every phrase in these invoice descriptions that could be read as promising more than the quote says (for example all, complete, including, as required, any, necessary). For each, give the phrase, the quote wording it conflicts with, and a replacement that matches the quote. Do not change any amounts.

Read each replacement against the quote before you adopt it. The assistant sometimes tidies wording into something that is shorter and also slightly wrong, so the quote is the source of truth, and the assistant's replacement is a suggestion.

The final claim: deposit credit and the last sum

The last invoice is where small errors compound, because it settles everything. Using the example and the deposit method described earlier, the position after the corrected claim #2 is: contract billed A 100%, B 100% and C 60%, which is $36,200, leaving $12,400 (C $6,400 and D $6,000). The deposit credit of $9,720 comes off the final invoice.

Remaining on the contract:  $6,400 + $6,000 = $12,400
Less deposit credit:                          $9,720
Final claim:                                  $2,680

Check: deposit $9,720 + claim 1 $19,400 + claim 2 $16,800 + final $2,680 = $48,600

If the variation is approved and billed, the contract total becomes $49,750 and the same check must land on that figure. For the assistant, a short prompt does it: list every invoice raised on the job, the quote total and each approved variation, and ask it to show the addition line by line so you can see where a mismatch starts. Then do the addition yourself as well. Where the job has retention, add one more check: the retention deducted across all claims should equal the percentage in the contract, and what is released later, the Final Claim Rebate on the final claim plus the retention claim after the retention period, should equal what was held. Simpro tracks the figure, and the check is that what it tracked matches the contract wording.

Two slips the same check catches: the deposit and the entry screen

The check is not only for the claim that has an obvious scope problem. Two quieter slips show up in the same routine, and both come from how the invoice is entered.

The wrong deposit percentage. An office raised the deposit for the $48,600 job at 25% because it copied the terms from the previous job. The invoice read $12,150 instead of $9,720, a difference of $2,430. Nothing in the invoice looked odd, but the check prompt had the quote's payment terms in block one, and "deposit 20% on acceptance" sat next to a 25% line. Put the payment terms in the quote block every time, not only the scope.

A percentage typed into the figure field. Simpro lets you enter a claim amount as a percentage or as a fixed figure at cost-centre level. In another invented case, the office meant 35% of cost centre C, $5,600, but typed 35 into the figure field. The line came out at $35. The recompute table shows it straight away: cumulative on C would be $4,035 of $16,000, which is 25.2% rather than the 60% intended. That catch depends on giving the assistant both numbers for every line, the intended percentage and the amount shown, so it can flag lines where one does not match the other.

Block 3, draft lines (each with intended percentage and amount shown):
1. Cost centre B, further 50%: $11,200
2. Cost centre C, further 35%: $35
3. Variation V1, core drilling: $1,150 (approval ref: none yet)

With that format, line 2 is the first thing in the reply: the stated 35% does not match $35 on a $16,000 cost centre. Whether a human or an assistant spots it, the fix takes seconds while the invoice is still Pending, and a credit note and a re-issue once it is not.

A four-minute routine, and a log that shows whether it works

The check only survives if it is short. This is the version I would give an office manager.

Keep a simple log with one row per claim: date, job label, claim number, flags raised, flags that were real, whether they were fixed before sending, and minutes taken. After ten claims two numbers matter. How many real flags did the assistant raise? And how many claims had none?

If ten claims pass with nothing real flagged, either your invoicing is clean or the prompt is too gentle, and you cannot tell which without a test. Once a month, take an old claim, alter one line (double a percentage, add an item the quote excludes), and run the check. If the assistant misses the planted error, change the prompt or stop relying on it. A control you have never seen fail is a control you have not tested.

Where Simpro's own help pages and videos fit

For button-level steps, Simpro's Help Guide is the right place. The articles to read are How to Create a Progress Claim, How to Use Invoice Stages, Deposit Invoice, Retention Claim and Request for Claim. Inside Simpro Premium, Help, then Walk Me Through, gives step-by-step guidance for tasks such as creating a retention claim, and the articles point to interactive lessons in Simpro's Learning Toolbox. Several of the old article addresses now redirect, so search the guide by title if a bookmark breaks.

What those pages do not do is check whether the content of your invoice matches your quote, because that depends on your documents. That is the gap this routine fills, and it works with any billing software, since the three blocks of text are all it needs. Simpro here is simply the software you invoice from, and the check does not depend on any feature of it beyond the stages described above.

For invoice wording and stage-payment layouts that are not tied to one product, see stage payment requests written with AI and deposits and progress billing for a painting business. Before you trust any total the assistant gives you, read why AI is bad at maths. When a checked invoice is out and unpaid, polite invoice reminders for trades take over, and what to ask when Simpro pricing is quote-only helps if you are still deciding what the software should cost you.

Simpro billing and AI check questions

Can ChatGPT connect to Simpro and check invoices automatically?

This tutorial does not rely on any connection, and I have not tested one. You copy the invoice lines and the quote scope into the chat yourself, with customer details removed, and read the reply before approving. Treat any automatic link as a separate project to scope and test.

Is it safe to paste invoice data into ChatGPT or Claude?

Send only what the check needs: line descriptions, amounts, percentages and the scope paragraph. Remove names, addresses, contact details and bank details, and use a business plan whose data settings you have read. If your contract limits sharing job details, ask the customer or your adviser first.

What if the AI's numbers and mine disagree?

Trust the recalculation you did in a spreadsheet or in Simpro, then work out why the assistant differed. Chat assistants often slip on long sums or assume figures you never gave. Use its output as a list of questions to answer, never as a total to send.

Do I deduct retention on every progress claim?

Only if your contract and the job set-up say so. Simpro's help describes retention set up at the start of a project and deducted from each progress claim, with part released on the final claim as a Final Claim Rebate and the rest through a retention claim once the retention period has passed. Check the contract first, then check the job settings match it.

Does the Pending stage stop an invoice reaching the customer?

Simpro's help says invoices can have two stages, Pending and Approved, and that unapproved invoices can be restricted from being emailed. The stages are optional, so confirm they are switched on in your set-up before you rely on them as a safeguard.

Further reads

• Simpro Form Builder: Draft Job Sheets and Safety Checklists With ChatGPT — The forms side of Simpro: job sheets and safety checklists drafted with ChatGPT.
• Simpro Electrical Reviews: Is It Worth It for a Small Firm? — Whether Simpro is worth it for a small electrical firm.
• Fergus for Builders: Job Costing and Progress Claims, With Fergus AI — How another trades tool handles job costing and progress claims.
• Roofing Accounting Software: Deposits, Progress Invoices, Job Costing, AI — Deposits, progress invoices and job costing in accounting software.
• Construction Job Costing With AI: Find Which Jobs Actually Made Money — Find out which jobs actually made money, once billing is clean.
• Quote to Cash: Connect Quotes, Invoices and Payments With AI — Connect quotes, invoices and payments end to end.
• Tradie Invoice Template: Tax Invoice Wording and Reminders With AI — Tax invoice fields, two filled-in tradie invoices, a rule-check prompt and a four-rung AI reminder ladder, with local rules to confirm.
• Construction WIP Report: What It Shows and How AI Builds One — What a work-in-progress schedule shows, a three-job worked example of over and under billing, and where AI helps and where it must not.
• AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.

Sources: Simpro Help Guide articles How to Create a Progress Claim, How to Use Invoice Stages, Deposit Invoice, Retention Claim, Request for Claim and Contractor Invoices, read 1 November 2026.