What are your temps on the warm and cool side?

Two of my ball pythons spend 60-75% of their time on the cool side of their enclosure, but you definitely want to make sure that your python is not sacrificing thermal preference in order to feel more secure. I like having two identical hides on each side, so that I know it isnt choosing a side because it prefers that hide. If the temps are ok, you could try switching the rock and the rock and see what side he chooses. You are probably going to want a second hide in the enclosure though.

Cheers,