As a side comment,
I had a vehicle years back that was all new mechanically, the motor was brand new (not rebuilt) as was the 4 row (staggered) copper brass radiator, factory pulleys, shroud, etc. It was basically all stock with no modifications. It ran 195 - 200 no matter what the speed was, the ambient temp, idling for extended periods, A/C on or off, didn't matter nor did anything i tried. After about 2 years it was totaled as it was just an old car of no real value at the time (would've been fixed today).
gauge accuracy was verified with a laboratory grade meter and thermocouple placed right next to the thermostat. the hottest it ever registered was 205 on a 100 degree day idling in traffic for 1/2 hour or so with the A/C on.
I just wanted to throw that out there for thought.