Confused about UTH And Thermostat

[Kaorte]

My substrate is about a quarter of an inch thick, but the plastic floor of the cage could read say 100* While the top only reads 91-92.

No point in the enclosure should be hotter then 95*F. If the bottom of the cage is getting to 100*, turn down your thermostat. If the snake needs too, it will move the substrate to get closer to the heat source. Sometimes they do this on purpose, and sometimes they don't. That is why you need to make sure that spot doesn't get too hot if they do happen to lay directly on it.