When the price of a Purchase Requisition (PR) is changed in Ariba Buying & Invoicing (P2P) to a higher value than the allowed budget and is submitted to ERP or S/4 HANA via SAP Integration Suite, managed gateway for spend management and SAP Business Network the following error is triggered:

Item XXX WBS element XXXXXX budget exceeded by XXX
Instance PRXXXX of object PurchaseRequisition could not be changed

However this same error is not triggered when Check button is clicked to perform the budget check, in this case system returns Success message. Why there is a different behavior?

The budget check functionality on ERP or S/4 HANA system is done against the quantity of the items of the PR and not against the price. When a Purchase Order (PO) is created for the PR previously sent to the external system, the PR open commitment is 0.

This PR will not consume any more budget and by changing the PR price only, the open commitment will not be changed hence will not consume more budget (will still be 0), so when the budget check is performed no error is triggered, only when the document is submitted.

Only when the PR quantity is increased the commitment will also increase, the external system will then consider that more budget is being consumed and if the budget exceeds the stipulated value the error is thrown for the budget check functionality.

For more information about this scenario refer to Ariba Real time budget check always returns Success for price changes in the V2 version of Purchase Requisition via Managed Gateway for Spend&Network Integration to SAP ERP and Commitment reduction for purchase requisitions

SAP Integration Suite Managed Gateway > Managed Gateway for Business Network SCC > Managed Gateway for Buyer Business Network SCC