Ball python staying on the cool side?

Ever since my Cornelius was finished shedding he hasn't left his cool side. He would sometimes stretch his body alongside the tank and have his face in the hot side, but often his body stays on the cool side. He's been like this for 5 days. The temperatures always stay at 80 degrees on the cool side and 85-90 on the hot side and I have one of those digital ones where I can shoot inside the tank and see what the temperature is and everything seems to be in good conditions. Should I be worried? Maybe I should keep the hot side a few degrees cooler? Or perhaps this is just what happens to some snakes after they shed? I would be grateful for some helpful answers :)

I've been under the impression that the cool side should be between 75-80 and the hot side 85, 90 seems too hot to me for his warm hide, Mine generally hangs in his warm side all the time it's 86 every time I check it.

I wouldn't even worry about it. After double checking your husbandry and checking the animal for any signs of ill health, you're pretty much done.
I've double and triple checked temp's in the past over the same thing thinking I must have something off kilter but, most of my balls are to be found in their cool hides except after feedings. There is the occasional foray into the warm hide when I don't expect it but, it is so occasional as to be nearly insignificant.

Edit: One other thing you could check is the calibration on your IR temp-gun.