Uhm, this is simply not true. How are you measuring brace? From the grip, right? If you construct a grip where the throat is closer to thestring than the original, it is inescapable that you have changed the brace, and will now require a longer draw length.
you have not changed the brace heighth, you have only made the draw longer which will effectively make the bow aproximately 11 FPS faster give or take but the effective brace heighth or the reflex of the riser has remained the same
agin I say the only way to change the effective BH is to shorten the limbs.