jfast, I'm not familiar with a Viewsat Extreme receiver or a Saab HH90 rotor, thus my chances of being able to help you are not the best.
I have no idea why, whenever you try to go to 110 or 119, your rotor moves west a little and then returns to center.
It sounds to me like you might be a little mixed up regarding how USALS works. First, you must enter the longitude and lattitude of your house. (You only have to do this once.) Once USALS knows this, it can calculate where to point the dish for any satellite location, such as the satellites at longitudes 110, 119, 105, 123, etc. Thus it has to know the position (longitude) of each satellite you want to receive. Your receiver probably came pre-programmed for most of the satellites you will be looking at. So, your receiver already knows the longitude of those satellites. If you want to view a satellite that is not pre-programmed into your receiver, then you'll have to enter it, giving it a name AND entering its longitude. Once you enter the longitude, USALS has all it needs to know in order to point to the satellite.
If in bolting the rotor to the pole, you do a great job of pointing the motor exactly straight south, and if your pole is perfectly plumb...and if you set your rotor's elevation accurately and you set your dish's elevation accurately..........then USALS can direct your rotor to accurately point to each satellite. But if any of that stuff is off a little, then USALS will be off enough for your signal to be less than maximum. If the signal is low on a satellite, then change the motor mode from "USALS" to DiSEqC...and you can then nudge the position a little east or west, in order to maximize the signal.
"How well the DiSEqC mode works for you" is a measure of how well you set up your dish. If you can't get a signal by pointing your dish with DiSEqC, then you need to improve your motor elevation/dish elevation/rotor body straight south on the pole. By far the greatest source of error is in getting the rotor body bolted to the pole straight south. Generally the best way to do this is by having USALS point to your southern-most satellite. You live at longitude 90.8. Satellite G11 is at 91.0. Very close! So close that, if your rotor is in the center postion to begin with, it will move west only an extremely small amount (if at all) in order to get to the G11 position. Once you do this, then you rotate the rotor body on the mounting pole to the postion of maximum signal for G11. But you must be sure that the signal you are receiving is from G11, and not an adjacent satellite. Do a blindscan and compare the results to Lyngsat. Once you are sure you're on G11, securely tighten the clamps holding the rotor body to the mounting pole. Your rotor body is now exactly straight south on the mounting pole.
Good luck.
