I got some expensive thermometers and some cheap ones----yep most all read a little different so Here is what I do and would do. I would place the thermometers in the middle of the hot incubator----placing them where they will be at egg height having them all about the same height-----and allow...
What type thermometer have you got inside? Where do you have it placed? What does the owners manual say? There is so much difference in your readings that I would have to have a 3rd opinion---Unless the one inside is real close to the heater.
Once you get your temp right---putting the eggs in...