[wejones]

Regardless of whether the dish is aligned perfectly or not, USALS assumes that the motor's zero position is correct. The motor's zero point is not always correct. Mine was off a couple degrees, and therefore USALS won't work (unless I lie to it about my longitude).
So unless you assume that calibrating the motor's zero position is part of the alignment, then USALS doesn't always work.
I *THINK* that with most motors, that you can calibrate the zero position just by manually setting it to zero and doing a hard reset. I've never bothered doing that on mine, because I was afraid that it would change all my diseqC-1.2 positions, but I think it would work.