Can you change the longitude setting for a specific sat in USALs? I've done that on my MicroHD but not sure if you can on an A3. Small increments like from 74.70 to 74.65 or 74.75 seem to work best for tweaking. I know I've run into that situation on one or two sats but don't remember off hand which ones.
I was doing the same same thing, that is, fudging the LONG settings after a severe wind storm re-adjusted the dish. I reset the LONG to the correct value, then with USALs sent the dish to 83W my near true south sat. Went up on the roof and loosened the bolts holding the motor to the mast and tweaked for max Q. Also tweaked the dish elevation while up there. It took longer to set up the STB and monitor outside then the actual motor/dish alignment.