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