Devon,
A lot depends on the site/situation of the incubator.
Ideally your looking for an even room temp, with not too many temp fluctuations.
Eggs are naturally cooled when the hen leaves the nest, and she would regulate higher temps better.
It sounds like your incubator is up and down a bit.
I find the fan assisted one's have to be around 37.5, I have mine alarmed at .2 deg for high temp.
Still air on the other hand I have set at 38 deg, with good results.
The hatchings this yr have been dry.
Even temps are the best imho, but that can be difficult I know.
Find the best spot to place