If my company uses the 100% deduction, does it pay no corporate tax at all?

It may still pay. The deduction is not among the items that can be deducted in the domestic minimum corporate tax calculation. The tax payable cannot fall below 10% of corporate earnings before the deduction, so even where the ordinary calculation comes to zero, the minimum tax difference is paid. Companies starting business for the first time are outside the minimum tax for three accounting periods, including the one in which they start. Income taxpayers are not subject to a minimum tax.