Ken2,
Please have him check his owners manual again on the 96 Ford PSD. It call for Mercon, but not dual rated Mercon and Mercon V. This is an E40D and requires only the Mercon rating. Even the 01 4R100 is the same as far as fluid. On 02 and above I don't know for sure.
Mobil I ATF meets the spec. and Schaeffer's semi syn meets the spec. Neither are dual rated.
Now with all that said, the Amsoil, dual rated ATF seems to work great for this transmission in spite of the statement contrary in the owners manual. About 50% of all people I know use the Amsoil ATF, 40% use Mobil I and alot who race or do tractor pulls use Schaeffer's. I do see a few using the Royal Purple also. Now this is just in the people that I know. On the diesel boards, about 50-50 between Amsoil and Mobil I. I have never heard a complaint on either one, in fact both are highly thought of. IMO