For a Purchase Order (PO) line item with amount-based receiving, the total amount accepted on the line is different from the sum of the individual PO's receipts.

Even after checking the total amount received and invoiced for the PO, as well as the ranking and tolerances for the invoice exception type, the PO Amount Received Variance exception is still not firing when we expect.

Enable the self-service parameter Application.Receiving.AllowReceivingWithoutDeductingTax.

There are taxes, charges, or discounts on the PO, and the parameter Application.Receiving.AllowReceivingWithoutDeductingTax is set to No.

When the parameter is off, then all receipts created in the SAP Ariba Procurement application considered as referring to the PO line item's amount after all taxes, charges, and discounts are applied.
However, the system calculates the received amount prior to taxes, charges, and discounts in the backend, and this hidden value is counted against the PO line's amount accepted.

When the parameter is on, the all receipts created in the application are counted against the PO line amount before any taxes, charges, and discounts are applied, so this value is directly applied to the amount accepted on the PO line.

Refer to the topic CP-13484: Specifying the amount without taxes, charges, and discounts in amount-based receipts in the SAP Ariba Applications 2005 (Q2 2020) release guide for more information.

Purchasing > Receiving
Purchasing > Receiving > Receiving Accumulators