Each Invoice line allowance (BG-27) shall contain an Invoice line allowance reason (BT-139) or an Invoice line allowance reason code (BT-140), or both.
//cac:InvoiceLine/cac:AllowanceCharge[cbc:ChargeIndicator = false()] | //cac:CreditNoteLine/cac:AllowanceCharge[cbc:ChargeIndicator = false()]exists(cbc:AllowanceChargeReason) or exists(cbc:AllowanceChargeReasonCode)