That's not entirely true. seatpost height to bottom bracket is relative to your leg length (725 = 6" seatpost showing, Brassknuckle 6.5"), The head tube length matters when it comes to how much spacers you use/saddle to bar drop (725 = 110mm, Brassknuckle = 150mm), but actually setting up both bikes "the same" (brass is 1" shorter virtual tt) would = 15mm of spacers on 725, no spacers on brass. If I threw a 70mm stem on 725, or a 95mm stem on the brass, the position would be "the same"... the frames definitely handle differently, but fit wise its the same setup.

I can not think of any instance where a larger frame and a *Less than 70mm stem would be more ideal than one frame size smaller and a longer stem. But feel free to prove me wrong.

There are frames made for long leg + short torso, as well as short legs + long torso. Maybe the geo of the bike is wrong, and my advice to go one frame size smaller does not apply within the same make and model of frame.