Invisible supplier overpayments: how to detect them
By Nicolau Matarrodona, founder · Published · Updated
Supplier overpayment recovery means finding the invoices you paid above the agreed price, above the quantity received or twice, and reclaiming the difference from the supplier with a credit note. Detecting them before payment costs less than recovering them afterwards. Many go unnoticed because nobody compares each line: they are invisible supplier overpayments. It is not fraud. It is not malice. It is the mathematical consequence of reconciling invoices by totals instead of line by line. Here we explain how those overpayments are generated, how to detect them before paying and how to recover the money.
What is an invisible overpayment
An invisible overpayment is any euro you pay a supplier above what was actually agreed and delivered, without your system detecting it. Three sources:
- Invoiced price above the price on the PO. Price change not communicated, miscoding, unfavourable rounding.
- Invoiced quantity above the quantity received on the delivery note. Broken goods returned, partial receipt not updated.
- Duplicate invoice. The same cost paid twice because the supplier resends it or due to a team error.
Why they become invisible
Three mechanisms keep these overpayments from being detected:
1. Matching by totals, not by lines
If you compare invoice total vs PO total and the difference falls within your tolerance margin, you approve. But two errors on different lines can offset each other in the total. Here we go through the numbers.
2. Global tolerance, not per line
A 2% tolerance applied to the invoice total allows large variances on individual lines. A 50 EUR variance on a 50 EUR line is 100% on that line, but only 1% on a 5,000 EUR total.
3. Volume without time
An SME with 600 invoices/month and 80 suppliers cannot review every document line by line manually. The statistics work against you: 4-9% always slips through.
The actual numbers
| SME volume | Overpayment low rate (4%) | Overpayment high rate (9%) |
|---|---|---|
| 200 invoices/month, average ticket 1,500 EUR | ~12,000 EUR/month | ~27,000 EUR/month |
| 500 invoices/month, average ticket 1,500 EUR | ~30,000 EUR/month | ~67,500 EUR/month |
| 1,000 invoices/month, average ticket 1,500 EUR | ~60,000 EUR/month | ~135,000 EUR/month |
Not all those overpayments are at 100% of the amount. Assuming that when there is an overpayment the average amount is 5-10% of the affected invoice value, real annual loss is in the order of 4 to 6 figures depending on volume.
Market estimates based on sector benchmarks for companies with non-automated AP. Your actual figure depends on process rigor, industry and specific suppliers.
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How to detect them before paying
Three operational rules:
1. Compare unit prices pre-VAT
Invoice vs PO, line by line. No VAT, no rounding, no global tolerance.
2. Compare quantities vs delivery note, not vs PO
The PO says what you wanted. The delivery note says what you actually received. If you pay by what is invoiced without checking against the delivery note, you pay for what you did not receive.
3. Per-line tolerance (OR mode)
By default: 2% or EUR 1.50 per line; exceeding either threshold is enough. Configurable. If a line exceeds tolerance, raise an exception.
How ininvoice automates it
- Captures every invoice from the supplier email (Gmail).
- Extracts line by line (OCR/IDP) from PDF and images.
- Looks up the PO via fuzzy matching.
- Cross-checks unit price pre-VAT against the PO.
- Cross-checks quantity against the delivery note.
- Applies tolerance configurable per line.
- Detects duplicates with multi-criteria signals.
- If there is an exception, it holds the invoice with the reason visible until a person decides.
If all lines reconcile, it is ready for a person to approve; once approved, it is exported to your ERP ready to book. If a line fails, it shows you exactly which line and how much overpayment there is, so you can take it up with the supplier.
Supplier overpayment recovery: reclaiming past overpayments
If you have spent time without line-by-line matching, you have probably accumulated overpayments pending recovery. Reviewing the history is useful to:
- Identify invoices with variance not detected at the time.
- Raise the claim with the supplier.
- Negotiate a credit note or a credit on future invoices.
Worked example of one claim: an invoice line bills 120 units at 10.40 EUR against a purchase order price of 10.00 EUR. The overpayment is (10.40 − 10.00) × 120 = 48.00 EUR before tax. The claim to the supplier names the invoice number, the line, the PO price and the quantity received, and asks for a credit note for 48.00 EUR plus the VAT charged on that amount. Run before payment, the same line check is matching each invoice line with its delivery note, and the claim is never needed.
In distribution profiles with 6 months of history, it is not unusual to find 4-5 figures of recoverable overpayments. Estimate based on industry benchmark.
Do you suspect you are overpaying your suppliers?
Connect Gmail and match your real invoices against their POs and delivery notes. .
Frequently asked questions
- How do I know if I have overpayments?
- If your current reconciliation is by totals (invoice vs PO) or if you do sample review instead of exhaustive, you almost certainly have them. The question is not whether you have them, it is how much.
- Is it legal to claim overpayments back from the supplier?
- Yes. If the invoice exceeds the agreed PO or the delivery note received, the supplier is required to issue a credit note or a corrective invoice. Your tax adviser can guide you on specific cases.
- Is it not the supplier's problem, not mine?
- Yes, but the money is yours. And you are the one losing it, not the supplier. The responsibility to detect it is on whoever pays.
- How much does it cost to automate detection?
- Tailored pricing for your company: a proposal within 48 hours of seeing your invoices (annual volume, companies, ERP). No implementation fee. Annual contract. The proposal is weighed against the overpayments found in your own invoices.
Catch what slips past you today
Tailored pricing · proposal within 48 hours of seeing your invoices · no implementation fee · no consultant.