Where they hide at any given time has a lot to do with what's going on at the current time... My spotted hasn't moved from the warm end 35 degrees in the daylight hours since eating a large hopper mouse on Thursday night. It moves about briefly after dark. My Stimmie, right beside the spotted in an exactly the same setup is in blue and going to shed any time now and has remained curled up on the cool side, (25 degrees currently) for most of the daylight hours, shifting to the warm side just before dawn for an hour or so. To me, yours sounds o be behaving totally normal and as long as your temp readings are accurate and what you say they are, I wouldn't be concerned.