I'm in my first season, so certainly no expert, but I'd say that you should leave things as they are if your temps have stayed right for over two weeks. Experiment with probe placement and tstat settings after you hatch and the incubator doesn't have eggs in it. Personally, I decided to leave my tstat probe outside the egg tub, on the shelf near it. I am using a Herpstat set at 89deg, and the inside temps of the egg tubs are 89.5deg. Part of the trick is to minimize how often you open the incubator so you don't cause unnecessary fluctuations. I check on my eggs about every three to four days, and haven't had any problems (Day 28).