I recently bought a motor, and just got around to setting up and getting my motorized setup working. (SG2100 motor, Coolsat 5000 receiver and Winegard 2076 dish) After the initial setup, I used USALS for rotating the dish, but I noticed that many times the dish had to be adjusted several degrees left/right to get reception. (i.e. 123W was coming in on 119W etc...) After adjusting the motorized settings for the particular satellites the would come in come in good.
Also, I noticed that sometimes after going from one satellite position to an extreme satellite position and back(i.e. AMC9 to Galaxy27 and back), the first position would be off, and had to be readjusted.
My question is whether this is normal, and whether using USALS or DisEqC 1.2 makes a difference?
In my opinion, I doubt that it has anything to do with the pole being level, although it COULD be that the pole is MOVING, ie not rigid. And in theory there should be no difference between USALS and DiseqC, provided that you are aligned properly and the motor is zero'ed properly. Although the way you "re-adjust" could result in a difference. The difference between USALS and DiseqC-1.2 is that in DiseqC-1.2, you save the sat positions in the motor, while with USALS, nothing is saved, it just goes a calculated number of degrees.
What you describe sounds to me like it could be free play in the gears of the motor. Another possibility is that for some reason, the motor is forgetting what it's zero is. Sometimes when my motor isn't going to a sat properly, I can send it back to it's zero reference position, and then back to the sat, and everything is OK.
Probably not related, but some motors won't work right on USALS properly if their zero position isn't really at zero. Ie my SG2100 goes to a couple degrees east of zero when sent to zero, so to use USALS I have to lie to it about what my longitude is. This shouldn't affect DiseqC-1.2. I think you can re-set the SG2100 to the proper zero with a hard reset after manually moving it to zero, but I've never bothered to do this on mine.
Anyway, I'm curious about what you're doing to "adjust" the positions when using USALS? Ie there are temporary manual (DiseqC-1.2 movements) that aren't saved, and there are DiseqC-1.2 re-sync commands, and you can change the longitude of the sat, or of your location. Ie about 4 different ways to adjust.
Also, you might try going past the sat, and coming into it from the other direction. IF this works, it suggests gear slop.