The withholding tax amount fields capture the portion of the invoice total that is withheld by the organization for legal reasons and not paid back to the vendor.

The ISR Retention (Impuestos sobre la Renta) field is used to capture the ISR retention component to withhold tax. This field can appear on Mexican invoices. The IVA retention component is captured in the regular withholding tax field.

These fields are not mandatory but the system converts any extracted values to a valid amount and uses these values in the validation calculation applied against all amount fields. It uses the following formula.

Invoice Total = Line item total + total tax + freight – discount – withholding tax – ISR retention

If line items are not mandatory, the amount fields can also be validated using the following formula.

Invoice Total = SubTotal + total tax + freight – discount – withholding tax – ISR Retention

Where Total Tax is the total amount of all taxes on the document. This can include Tax Amount and any other country-specific tax fields.

The tolerance for the above calculations is set in the Settings > Invoice Processing > Global Settings > Tolerance Settings and the system applies the tolerance based on the tolerance group lined to the currency of the invoice.

During export, the system outputs withholding tax as a separate header level field added to the ISR retention amount. The ISR retention field is also available as a separate export parameter. The system outputs the invoice total amount along with the withholding tax and ISR retention amounts added back on.

For more information on processing Mexican invoices, refer to Mexico.