I am guessing that you are not using probe thermometers to measure temps because that UTH temps seems awfully low. Even the smallest UTHs top at 110 when not regulated (which I am assuming yours is not).

If your ambient air temp is above 75* without the lamp, then there is no need for one. The UTH will take care of the hot side of 90-94*. Just make sure you get a thermostat or else you could burn your snake.