May 11, 2026 · Field notes

How three-way matching fails in busy AP teams

Desk with invoices and purchase paperwork ready for matching

When we test accounts payable, three-way matching looks tidy on paper and uneven in practice. The purchase order exists. The goods receipt sits in a warehouse system. The invoice arrives with a slightly different quantity or a freight line nobody expected.

Quantity tolerances that swallow real differences

Many Taiwan manufacturers set matching tolerances wide enough that a five-percent shortfall never reaches a human. During sampling we ask whether that tolerance was intentional for the commodity—or inherited from an old ERP default. Controllers are often surprised by how many invoices clear inside a band they never reviewed.

Receipts posted after payment

Urgent vendor relationships create a second pattern: finance pays on the invoice while warehouse posting lags. Attribute testing then shows a payment without a contemporaneous receipt. The goods may have arrived; the control still failed for the period under review.

What we recommend before the next cycle

Pick one high-volume vendor class and tighten tolerance only there. Align warehouse posting deadlines with AP payment runs. And keep a short list of “pay-without-receipt” approvals so testing can separate known exceptions from silent ones.

See how we test matching in an engagement →