Of the four slews you do, only the second error is different from the others by much at all - the three are very consistent - but I can't be sure if the sign of the error is reported - because "within" suggests it is an absolute value. If the sign is the same in all errors then it looks like a very good match to what I expect - and that is for an avx where I would expect less repeatability. Even if one slew is a bit off from the others - it would still tend to converge as long as the errors are adjusted after each move. Either way there is an overall bias and a great deal of the error should be removable. For a cge-pro I expect it to be better. If you don't remove the bias - it definitely won't converge.
And the other report above said it "kept hitting between 80 and 85 pixels." I can't be sure that is the exact same offset in each attempt - but if so is very good repeatability - on the order of a few arc-seconds - which is what I recall from my centering attempts with cge-pro.
Thanks for your contributions to this topic.
Frank