My question is about attic ventilation fan controllers (thermostat/safety shutoff).
     I’m updating my attic ventilation:  my home’s roof is too flat (2.5/12) and the total rise is all under 3′ so passive stack ventilation such as through a ridge vent will not do.  Also I understand that some believe that if you put enough insulation over the living space there is no need to vent an attic — I can see that may be the situation for some homes/climates but not universally.  Allowing the attic to heat up in my hot climate reaches temperatures that I understand will shorten the life of roofing materials, and insulation (even R38) is only as effective as the difference in temperature between both sides of the insulation — in my case I understand that might be over 80 degF daily for 3 summer months.   So I think in my case an attic exhaust fan is warranted. 
    I see that some smart controllers are coming out with attic exhaust fans, which cost no more than the standard attic exhaust fan thermostat/fire safety shutoff.  If you are going to the trouble of having a smart controller, my question is why not include two thermoprobes such that the controller can turn the exhaust fan on whenever (warm season) the outside temperature is cooler than the inside attic temperature;   and (cool season) whenever the outside temperature is warmer than the inside attic temperature –?      Since there is nothing added to the equipment install effort other than placing a second temperature probe just outside of an intake such as soffit vent (representative outside temperature), why not?
   Your constructive thoughts appreciated..   can anyone recommend such a dual thermoprobe fan controller that also has the fire safety shutoff ?