I don't think mine measures anything but the ambient temp because the temperature is almost always a few degrees below what the thermostat is actually set for. I've read elsewhere that that is actually normal.
I guess I'm just baffled as to what that interior dial was on my previous manual thermostat (whose name still escapes me!) and what use it served.
I may just end up calling for a service call to make sure that my heat pump unit is still functioning efficiently. (Sigh) I dread making those kinds of calls though because I've read all sorts of horror stories of bad service techs. Ah well.