"There is no such rule I was speaking of obtaining an advantage by backing out income tax effects from export prices as is done with VAT. WTO doesn't care if you have an IT or not but will not reward you for removing it if you do."
No FairTax supporter that I am aware of has ever implied that the FairTax would convey a "reward" from the WTO. We are simply looking to eliminate the bias that our own tax system provides in favor of foreign producers at the expense of our own producers now. The FairTax would tax imports and domestically produced items equally, which is a much better deal for US producers than what we now have and better than any other specific proposal that I am aware of.
Of course, I'm not counting the Nightmare Flat or the Nightmare VAT, which can be anything you want them to be. I said "specific proposals".
I have not claimed anyone said the WTO would reward for converting to the FT. Nor do I agree with you about the disadvantages to US exports under the current regime.