Tax passed in parent line of Service PO does not auto flip when creating an invoice even though the invoice transaction rule Copy tax from purchase order to standard invoice is enabled.

The default functionality is that tax can only be automatically flipped if passed in child lines of a Service PO.

The feature CSC-16389 must be enabled for your account.

This feature has been designed to allow tax details to flip from Service PO parent line to child lines and the same will be auto flipped when creating the invoice.

You will need to contact your Customer Success Partner(CSP) to check with the customization team regarding this feature and log a case to request enablement of CSC-16389.

SAP Business Network for Procurement & Supply Chain > Transaction Documents > Transaction (Invoicing)