Just alittle FYI for all.............most sending units for the temp gauge is near or close the outlet water neck to the radiator. So keeping that in mind, if everything in the cooling system is doing it's job, pump, fan and radiator, then the thing one has to remember is the coolant is being gauged at it's hottest point right as it exits the motor and goes into the radiator.
If the radiator is up to par, the temp drop across it should be 15-20 so the coolant going back to the motor is cooler and then the cycle goes on.