You can’t trust thermostat ratings

Gotta disagree with that. Everything I have ever seen or read stated that the temp on a thermostat was when it started opening. @RustyRatRod was an Oriellys manager for years, and I agree with him.
Oh GAWD well there's the gauntlet. LMMFAO. What a stretch.

But seriously, that's all I've ever seen @MOPAROFFICIAL as well was that the thermostat just begins to open at the rated temperature. It's fully open at "a little" higher temperature.

Oreilly. LOL That's a hoot.