ABR-1 TOM Placement vs StewMac

[guitar2005]

For years, I've been building guitars with tremolos and TOMs but never have I done a build with the ABR-1 TOM. 

This bridge has the particularity of having a little less saddle travel for the intonation and as such, I'm being very careful with the placement of the posts. 

The guitar will have a proper 24.75" scale length and the Stew-Mac calculator places the treble bridge post @ 24.811" (630.2mm) and an extra 1/8" (3.175mm) on the bass side. I usually just set the bridge so that the scale length makes it to the mid-point of the saddle adjustment, which means I rarely use the StewMac calculator for this.

I mocked up the whole thing with a nut, tuners and a bridge with the saddles in the middle position with the high and low E strung up. I proceeded to do a rough intonation check and placed the bridge where it seemed to be perfect. I checked the measurements and I'm at about 632mm from nut to center of the post on the treble side and about another 4-5mm for the bass side. 

Why the discrepancy between my values and the StewMac values? The fret board is correct in scale. Could it be that I should not have placed the saddles in the middle for the setup? I always like to have enough travel room for the saddles. The strings are new and had the same result with different strings.

I saying this, It is a little hard to get a good measurement from nut to the bridge post holes on the body since the neck is angled so there is a bit of an error there. 

Am I the only one to run into something like this?