Tax category taxable amount (ibt-116) = Σ Invoice line net amount (ibt-131) – Document level allowance amount (ibt-092) + Document level charge amount (ibt-099).
cac:TaxTotal[cbc:TaxAmount/@currencyID=../cbc:DocumentCurrencyCode]/cac:TaxSubtotalevery $category in cac:TaxCategory/cbc:ID satisfies ((count(../../cac:AllowanceCharge[cbc:ChargeIndicator=true()][cac:TaxCategory/cbc:ID = $category]) > 0 and count(../../cac:AllowanceCharge[cbc:ChargeIndicator=false()][cac:TaxCategory/cbc:ID = $category]) > 0 and (cbc:TaxableAmount = sum(//cbc:LineExtensionAmount[../cac:Item/cac:ClassifiedTaxCategory/cbc:ID = $category]) + sum(../../cac:AllowanceCharge[cbc:ChargeIndicator=true()][cac:TaxCategory/cbc:ID = $category]/cbc:Amount) - sum(../../cac:AllowanceCharge[cbc:ChargeIndicator=false()][cac:TaxCategory/cbc:ID = $category]/cbc:Amount))) or (count(../../cac:AllowanceCharge[cbc:ChargeIndicator=true()][cac:TaxCategory/cbc:ID = $category]) > 0 and count(../../cac:AllowanceCharge[cbc:ChargeIndicator=false()][cac:TaxCategory/cbc:ID = $category]) = 0 and (cbc:TaxableAmount = sum(//cbc:LineExtensionAmount[../cac:Item/cac:ClassifiedTaxCategory/cbc:ID = $category]) + sum(//cac:AllowanceCharge[cbc:ChargeIndicator=true()][cac:TaxCategory/cbc:ID = $category]/cbc:Amount))) or (count(../../cac:AllowanceCharge[cbc:ChargeIndicator=true()][cac:TaxCategory/cbc:ID = $category]) = 0 and count(../../cac:AllowanceCharge[cbc:ChargeIndicator=false()][cac:TaxCategory/cbc:ID = $category]) > 0 and (cbc:TaxableAmount = sum(//cbc:LineExtensionAmount[../cac:Item/cac:ClassifiedTaxCategory/cbc:ID = $category]) - sum(//cac:AllowanceCharge[cbc:ChargeIndicator=false()][cac:TaxCategory/cbc:ID = $category]/cbc:Amount))) or (count(../../cac:AllowanceCharge[cbc:ChargeIndicator=true()][cac:TaxCategory/cbc:ID = $category]) = 0 and count(../../cac:AllowanceCharge[cbc:ChargeIndicator=false()][cac:TaxCategory/cbc:ID = $category]) = 0 and (cbc:TaxableAmount = sum(//cbc:LineExtensionAmount[../cac:Item/cac:ClassifiedTaxCategory/cbc:ID = $category]))))