Solution : https://service.sap.com/sap/support/notes/454446 (SAP Service marketplace login required)
Key words :
change header fields, online transactions me22n, longer derived/changed, field poheader-pmnttrms, payment period reason, cash discount percentages, cash discount percentage, function module bapi_po_change, cash discount, pordch01 pmnttrms
Related Notes :
| 390742 | Customer enhancements not transferred |