Peter - to return to your last post,
I'm not saying that you'll find different tension outside the nut-saddle length, I'm saying that to achieve a given pitch on a given string at a given scale, there will only be one tension that will work. It will be same over the whole string, but changing the length outside the speaking part will not vary it.
Well, try and imagine you can slide the tailpiece of your Alembic back and forth. If you slide it back, you're stretching the string, so this will increase the tension, and therefore increase the pitch. To get the same pitch with the longer distance between bridge and tailpiece, you would actually have to tune down (decrease the tension).
Think of a tremolo bridge, you're making pretty minimal changes in the speaking length, with already noticeable effects on pitch, as well as on tension and stiffness - especially if you go dive-bombing EVH style.
So I'm not surprised that there is a difference in both tension and stiffness, between a one-piece bridge and a two-piece set. Or for through-body stringing, for that matter.