Just to check, are you doing extract or all grain brewing? If you are doing extract don't worry about this talk to mash tuns for the time being, because the people who make the extract already did that.
A thermometer in the boil kettle tells me 2 things, how close I am to a boil, and how much further do I need to chill.
While the boil is where some of the most complex chemistry in brewing takes place, lucky for brewers it is also one of the easiest to control. While temperature does play a role hop reactions, there are other reactions which require more heat. During the boil DMS is generated, and needs to be volatilized off. You need a vigorous boil to make sure the DMS stays out of the beer. As long as you have a nice rolling boil you are fine. Tweaking the boil-off rate will impact the melinoidan formation, and your final gravity, both of which really just require consistency, vs a specific measurable value.
As for temperature in the boil, physics will not allow you to boil too hot. If you are getting different temperatures in various locations in the kettle while boiling, either your thermometer is wrong or you are not boiling vigorous enough. A vigorous boil will cause a turning motion of the fluid in the kettle, mixing everything. What the actual temperature of the boil is really is a moot point, it will be 212 F, with some variability for the various corrections listed above. But in the boil the temperature is not the issue, the chemistry is not that particular. You are well in the range where the reactions will happen appropriately.
If you are talking about the temperature while steeping grains, then the temperature is important, but make sure to stir the the water well (same with hot liquor) before reading the temperature.
Don't take any more faith in anything I say than you would anyone else on the internet. If you listen to what I say, then hurt your self or break something it is your own fault, I am just expressing my opinion or experience.
THINK for your self!!