Mechanically, the system is the same as in earlier models. Electrically, it is quite different.

You can eliminate the effects of the duovalve by clamping the outlet hose. Then see what you get. These are showing higher than ambient, so you would seem to have some coolant flow through the heater core.

Clearly there was too much refrigerant when you got the 28 reading. That will trigger the auxiliary fan at high speed.