no "expert" by any means, but isn't there a "pinion correction" the dealer can do with a factory scan tool ? i remember seeing that in newer FSM's, but i don't remember [if i even knew in the first place] when this started. i believe this was to account for transmission replacement and tire sizes.
john kunkle would know for sure ! he is a transmission GURU. member transman is also, so hopefully either of those gents will chime in and set this straight with the correct info.