If the frames of the two bikes are different enough geometries and tube lengths, then simply transferring measurements to your contact points will leave you in less than optimal position.

Different seat tube angles, reach of the bars and stem added to the frame reach, length of cranks, fork rake and head tube angle all can make a fitted position on one feel right but so wrong on another.

When you move your seat you are changing your position over the BB and that not only affects how much weight you feel on the bars, but more so how you perceive the fit of the bike itself. And the least weight on the bars you can get is not always the best fit for power output. At least not for me.