I'm surprised you're getting signal at all if you started at 100 skew and backed off to 80. You totally disturbed the geometry of the dish when you went to the other side of 90.
My advice is to go back to the correct skew for you ZIP and leave it there. Tweak Elevation and Az.
My advice is to go back to the correct skew for you ZIP and leave it there. Tweak Elevation and Az.