[IBR-062-OM, IBR-105-OM] - Document level allowances (IBG-20) with Document level allowance VAT category code (IBT-095) as 'E' (Exempt) or 'Z' (Zero rated) MUST have a Document level allowance VAT exemption reason code (IBT-196).
IBR-062-OMubl:Invoice/cac:AllowanceCharge[cbc:ChargeIndicator = 'false'] | cn:CreditNote/cac:AllowanceCharge[cbc:ChargeIndicator = 'false']not($cat=('E','Z')) or cac:TaxCategory/cbc:TaxExemptionReasonCode