what are the possible cash flows to be deduct from revenues to arrive at operating cash flows on which we calculate tax. whether we deduct setup fixed cost or any other relevant fixed cost.
you subtract all incremental (extra) future cash flows relating to income statement items.
If there are extra fixed costs payable then they should be subtracted (but not if they have already been paid – sunk costs, and not if they are not extra costs (so not if they are simply an apportionment of an existing fixed total).