Dominant in healthcare. The GPO negotiates with manufacturers; members buy at contract prices through wholesalers; the manufacturer pays the GPO an administrative fee as a percentage of contracted sales.
Because the fee is calculated on a sales basis reported by wholesalers, an error in chargeback validation propagates: an invalid chargeback is paid *and* generates an admin fee on top of it. The two errors correlate and run the same direction, which is why chargeback validation in this sector is worth more than its face value.