Interesting, I just replaced both sensors but didn't have to perform any calibration and haven't seen any codes pop up as a result. I'll give the referenced ISTA procedure a whirl next time I'm hooked up just to see what happens.

OP, is this on an I-6 or the V-8? Not that I'm sure it matters.

Only other random thing I can think of is, what did you torque the fasteners to? IIRC, that's a 6mm torx bolt and should take 10NM.