If I understand you correctly that means your using the thermostat probe to measure temps INSIDE the cage rather than directly on the heat source.
That is NOT what the t-stat was built to do. It will shorten the lifespan of the UTH as well as if water or urates gets on your t-stat probe, the temperatures will spike- cooking your snake.
Use the T-stat probe directly taped to the UTH and a separate thermometer probe in the enclosure.
If the UTH has to be up to 105 to get the lowest temperature of 92 in the cage, then theres not a whole lot of problems with that. My t-stat reads 104 and gets temperatures perfect on the inside of the enclosure.