Universal code to be valid for payment/collection plans is determined in UniCodefield of payment (collection plans. The code selected in this field is determines universal code default of payment plan lines.
If a different universal code will be used in payment plan line, it must be specified in related field of payment plan line.
Universal Code column takes place in Payment Transactions window reached by F9 menu of invoices. This column's universal code default comes from UniCodefield of payment/collection plan's related line. If payment transactions are combined, this field's value comes from payment plan line which selected in invoice. It can be changed.
When sending invoice, the lines without universal code info cannot be added to UBL-TR format. Only the lines having Universal Code are transferred to UBL-TR format and added to invoice in UBL format.