I have a 2 stage geothermal system and a vision pro th8000. Does anyone know what allows 2nd stage heat or cool to energize? Is it based on how many degrees off of setpoint? It seems like the stat will run first stage for a long time because the geothermal unit is running at 70% capacity on first stage. I would like to use 2nd stage sooner to cut down on run time, but I don't think this stat is capable of adjusting the staging.