[IBR-064-OM, IBR-106-OM] - Document level charge (IBG-21) with Document level charge VAT category code (IBT-102) as 'E' (Exempt) or 'Z' (Zero rated) MUST have a Document level charge VAT exemption reason code (IBT-198).
IBR-064-OMubl:Invoice/cac:AllowanceCharge[cbc:ChargeIndicator = 'true'] | cn:CreditNote/cac:AllowanceCharge[cbc:ChargeIndicator = 'true']not($cat=('E','Z')) or cac:TaxCategory/cbc:TaxExemptionReasonCode