So, there you go. No problem.
If you want to know the operating temperature on the thermostat, you can open a discarded unit and see if/what is etched or printed/stamped on the unit.
I have a 80 degree unit in mine. Today we have a cold day here, 13 degrees. I made sure the car was filled with coolant, and off I went. Leisurely driving. Heater off. Temperature on dash showed 80 degrees rather quickly, within 2 km I guess. And then it sat fairly constant at 84 degrees for maybe anther 5 km. After that it started to rise to about 95 and go up and down with stops starts and speed.
So to me it looks as if when the first batch of cold water in the radiator is being used, things are pretty stable, and you will see temperatures of maybe 5 degrees above opening, until the water in the radiator has been through the engine. Then the flat spot moves up another 5 to 10 degrees.
I think the Chinese have started fitting 80 odd degree thermostats in their units as well. And to me, that makes a lot of sense.
And I promise you, that will never make the fuel mixture rich!
So I hope you now feel much better!!