Sounds like you are lucky you never got a burn. An unregulated uth can get much hotter than what you reported. Good thing your snake didn't use it.
All of my uth are on tstats but hardly any of my snakes use their hotspot. It would probably be about the ratio you first described.
The only thing that matters is all the temps in the cage are acceptable. If they are it didn't matter where the snake likes to be.
Get yourself a IR temp gun so you can better monitor surface temps. They are cheap on Amazon.