As long as you're absolutely sure that the 82-85 degree reading is accurate , then it should be fine.
To measure the maximum temp, you need to be using a digital thermometer probe on the floor surface or a temp gun, rather than a cardboard strip or plastic dial-type thermometer which can be more than 10 degrees out. Also don't rely solely on the settings on the stat, as they can behave slightly differently depending on what make/model or size of UTH you have. I use the stat dial as a rough guide, then tweak the temp from there if needed.
As long as you have those bases covered, then your Corn is safe to sit on the warm side.