Ball python won’t use heat pad properly?

[aminevoo]

Hello! I’m brand new to this website and also to the reptile-keeping hobby. I got my first ever ball python almost one month ago and he’s currently living in a 33qt plastic tub (the brand Really Useful Box). He’s almost 9 months old and I’ve heard that this size tub is technically “too big” for him, but I blacked out the sides and have 2 secure hides (black Pangea plastic hides) on both sides for him with fake foliage thrown in there for extra cover. His ambient temps are around 80° everyday and the hottest point of his heat pad is around 90°. He’s eaten twice already and comes out of his hides at night to explore and then sleeps in his hides all day, which I’ve read is normal ball python behavior so I’m not worried about him being stressed out.
I started noticing a weird pattern a few days ago though.
I set up his heat mat one one side of the tub with a highly-recommended brand of thermostat (herpstat) so it should be reliable. I measure the surface temps of the hot side almost everyday with a temp gun and it regularly measures the basking spot temps to be 90° on half of the heat pad, and around 85° closer to the edge of the heat pad.
For some reason though, whenever he goes into the hide on the hot side, he moves it all the way to the edge of the heat pad where the surface temps measure 85° at the hottest. He’s been doing this everyday and if I move the hide back onto the heat pad, he’ll just move it almost completely off the edge of the pad again. His hides are the black plastic Pangea ones that are super lightweight, so they’re easy for him to move around. I’m not sure if I should go and buy heavier hides for him so he doesn’t keep moving it around, but his behavior is making me wonder if his hot side is too hot for him which makes him want to move to the cooler section of the heat pad?
Again, the hottest section of the heat pad is 90° and it’s big enough for him to curl up fully on, so it technically shouldn’t be “too hot” for him…unless those black plastic hides trap in heat and make the hot spot seem hotter to him?
i forgot to add, his cool side temps are around 77° and he used to thermoregulate normally by moving between hides periodically, but now he just insists on moving the hot hide with him to the cool side of the tub for whatever reason.
Sorry this was extremely long! I just wanted to provide as much info as possible to explain the situation because I’ve never heard of anything like this before.

[Bogertophis]

From what you've said, I'd lower the temp. on the heat pad- and YES, heat does build up under their hides also...especially when your house is already warmer in the summertime. It may help in winter, but right now it's likely too warm- it helps to pay attention to what your snake is trying to tell you with their actions & choices they make. Try it 85*- see how he reacts & uses it.

Good question, &