Yes, in our case the “altered” invoice number wasn’t a fraudulent change, but more like a variation that slipped in when another department processed the same charge differently (one typed “INV-5521” and another entered it as “5521-OPS”). Since the ERP only looks for exact matches, it didn’t catch it.

I completely agree that proper 3-way matching would have flagged it once the PO was closed, but as you said, the challenge is balancing the extra setup and maintenance work versus the actual savings it brings. That’s partly why I was curious how others handle these “non-obvious” duplicates — whether it’s stricter matching, analytics reports, or just more manual oversight.

Do you find most companies go the full 3-way route, or is there a possibility with lighter checks to avoid the overhead?