The OP's "hot side" is a bit over 93*- which IS too warm- & that's assuming that the temperatures are accurate as taken- but what if they're a bit off?
If you're offering "the perfect gradient" then it's not the same thing- snakes know what they need & when they need it. They manage to survive in the wild by slowing their metabolism according to the seasons & availability of food. It may be that there is less light in his "tub", & right now the day lengths ARE getting visibly shorter, indicating to snakes that fall is here & winter won't be far behind, so maybe it's time to think less about eating. It's thought that snakes pay attention not only to temperatures but also day-lengths, which is why they should always be provided a "photo-period".