I just came down from the roof top with good news. Arc is tracking perfectly now. I had to change motor elevation settings to get it working properly.
One thing I can say for certain is that Pansat's PM900 motor manual &
installation instructions absolutely SUCK. Aside from being vague & unclear, their "Quick Installation Guide" supplement (which Pansat USA tech guy told me corrects errors that are in their re-labeled
SM3D12 manual) gives inaccurate setup information as well.
In this case, I would have been better off to not read Pansats "Quick Installation Guide" at all. For my location, their instructions said to set the motor at 36.3 degrees and the dish at 24.0 degrees elevation. The elevation settings that finally worked as they should were with the motor at 43 degrees and dish at 25 degrees. And, 43 degrees is, in fact, my actual latitude (42.5) so the SM3D12 manual is correct but Pansats Quick Installation Guide" is wrong.
By the way, I really meant "relabeled SM3D12 manual". In fact, if you put the PM900 and the SM3D12 manuals side by side, the only difference is the change of the company names used in them.