I think so Income tax from the total invoice before adding VAT

I think so
withholding tax from the total invoice before adding VAT

If you want the withholding tax to be calculated on the subtotal, you must enter it as an amount rather than a percentage. This is explained in the Guide: https://www.manager.io/guides/12346. However, in most jurisdictions where tax is withheld at the source, the calculation is performed on the total including other taxes.