While his cool side temps are a bit warmer than I like, his hot side temps are spot on imo.

OP they do what they do to thermo-regulate, being cold blooded the only way to alter their body temp is to move.
They will move back and forth, up and down, to find the temperature that they like the best at that moment, so what you're describing is perfectly normal.
I have a few snakes with hides, most do not have them, but the ones that do have them do not always sit in them.
Sometimes under, sometimes over, sometimes on the cool side, it's just what they do