[BR-CO-25-SG]-In case the Amount due for payment (IBT-115) is positive, either the Payment due date (IBT-009) or the Payment terms (IBT-020) shall be present.
BR-CO-25-SG/ubl:Invoice/cac:LegalMonetaryTotal/cbc:PayableAmount((. > 0) and (exists(//cbc:DueDate) or exists(//cac:PaymentTerms/cbc:Note))) or (. <= 0)