[ALIGNED-IBRP-057] - Either both or neither Allowance base amount (IBT-093) and percentage (IBT-094) MUST be provided.
ALIGNED-IBRP-057ubl:Invoice/cac:AllowanceCharge[cbc:ChargeIndicator = 'false'] | cn:CreditNote/cac:AllowanceCharge[cbc:ChargeIndicator = 'false'](cbc:BaseAmount and cbc:MultiplierFactorNumeric) or (not(cbc:BaseAmount) and not(cbc:MultiplierFactorNumeric))