# Duplicate invoice checks in Sage 300 for builders

Sage 300 covers part of duplicate invoice checks on its own. Subcontractors resend claims when payment is slow. A resent claim with a new invoice number looks like a new bill and can be paid twice.

## Why it matters for builders

- Progress claims are numbered and often look the same except for the claim number and amount. Duplicates hide in the small differences.
- Plant hire and bin companies bill weekly with similar amounts, so a repeat charge is easy to miss.

## For builders in Sage 300

- Set the duplicate rule once on a vendor group for subcontractors. Vendor and Amount and Vendor and Date each take Ignore, Warn or Stop. New vendors in the group start with that setting and you can change it per vendor.
- A subcontractor on a fixed monthly claim will repeat the same amount. Use Warn on that group so a real claim is not blocked. Keep Stop for one-off suppliers.
- The check covers invoices, debit notes and credit notes from the vendor.

## What Sage 300 does on its own

Accounts Payable can check for duplicate invoices at vendor group and vendor level. The check uses the same vendor and amount, or the same vendor and date. The system will also not let you create duplicate document numbers for the same vendor.

- Check works within one vendor only.

The check is vendor with amount or date, not an exact invoice number test across vendors.

What you need and the setup steps: https://www.pulsify.tech/duplicate-invoice-checks-for-sage-300/

## Example

Example Formwork Pty Ltd emails claim 5 as INV-0506 for $22,000 ex GST. Two weeks later they email it again as INV-0507 with the same amount and the same job reference.

- Claim 5, formwork level 4: $22,000.00 (Same supplier, amount and job as an earlier bill)
- GST: $2,200.00 (Matches the earlier bill)
- Invoice number INV-0507 (Different from the first number, so a number-only check misses it)

The check flags a likely duplicate on supplier, amount and job. The second bill goes back to the subcontractor instead of the pay run.

## Common mistakes

- Checking only the invoice number, so a resent claim with a new number gets through.
- Paying a final claim without checking it against progress claims already paid.

## Step-by-step guides for Sage 300

- How to stop paying a vendor invoice twice in Sage 300: https://www.pulsify.tech/how-to/stop-paying-a-bill-twice-in-sage-300/

## What Pulsify adds

Pulsify checks every invoice for a duplicate, including bills keyed straight into Sage 300, and asks before approval. Pulsify connects to Sage 300. We set up the connection for you. More: https://www.pulsify.tech/duplicate-invoice-checker/

## Common questions

### Will Sage 300 stop a subcontractor's claim sent twice?

It can warn or stop when the same vendor and amount appear again. It can do the same for the same vendor and date. You pick Ignore, Warn or Stop for each test on the vendor group or the vendor. Use Warn for fixed monthly claims so real claims go through.

### Should a final claim be checked against earlier claims?

Yes. A final claim should equal the order value plus approved variations, minus what you have already paid and retention you still hold. Check the running total before you approve.

### Does Sage 300 stop duplicate supplier invoices?

It can warn using a setting on the vendor group and vendor: same vendor and amount, or same vendor and date. It will not allow duplicate document numbers for one vendor.

## Sources

- https://cdn.na.sage.com/docs/en/customer/300erp/2023/open/Sage300_AccountsPayable_UserGuide.pdf
- https://www.nsw.gov.au/housing-and-construction/compliance-and-regulation/security-of-payment/responding-to-a-payment-claim

### Also confirmed by

- Greytrix Sage partner blog, 2018: https://www.greytrix.com/blogs/sageaccpacerp/2018/03/12/prevent-duplicate-invoices-in-accounts-payable/

Source: https://www.pulsify.tech/duplicate-invoice-checks-in-sage-300-for-builders/ (last checked 2026-10-19)