[ibr-042]-Each Invoice line allowance (ibg-27) MUST have an Invoice line allowance reason (ibt-139) or an Invoice line allowance reason code (ibt-140).
ibr-042
cac:AllowanceCharge[cbc:ChargeIndicator = false()]
exists(cbc:AllowanceChargeReason) or exists(cbc:AllowanceChargeReasonCode) or not(exists(ancestor::cac:InvoiceLine|ancestor::cac:CreditNoteLine))