Wendy, my female does the same thing.

She sleeps under her newspaper on the cool side. I thought my temps were to hot but they read out fine, and she does move around to the warm end at night.
Although last night after I fed her (which is the first time i fed her in her tub and not the feeder cage) she came out and stayed in her shoe box hide.

Seems like your being a responisble owner and doing everything right.
Good luck and congrats on you new addition!