Attention Readers! I have just learned that my home does not have five thermostats. It has seven. The sixth thermostat was discovered in the 3rd floor bathroom. It operates the radiator that hangs on the wall and holds towels. I missed this one because Hubby generally keeps this one off. The main 3rd floor thermostat tends to keep the bathroom warm enough. I occasionally turn it up because I like a warm towel. Since he seldom hangs his towels up, he wouldn't know what he is missing.
The seventh thermostat is in the kitchen, tucked away in a corner. It operates the radiators in the kitchen which were put in new when we remodeled. At least that's the official story.
I'm thinking a little thermostat hanky panky may have been going on between those two heat meters in the back room.