What's the deal with being .01 out of parallel? The slots will either:

a) be cut so that they cross, which will "average out" the error, or

b) be cut so that the slots are parallel to each other (but slightly off
parallel with the surface)

in either case, so what? There's a lot more than .01 slop in the
biscuit itself, I would think.

I also think that throwing that last thousandth in there on a
measurement for wood is false precision, at least for the vast majority
of woodworking. Shoot, I've got a micrometer, good to 0.0001" (so the
box says). I wonder how many different measurements I'd get if I
checked the thickness of a biscuit in the same place a dozen times?

-j