You should have purchased the EX with ATC then she could leave it at 70 and forget about adjustment.
With the LX unit, the mode needs to be set at the desired position, then set the temperature control, set intake outside/inside, set fan speed, and if a/c is needed, that needs to be manually turned on.
Winter put to floor position, temp to max, outside air, and then she just needs to adjust the fan.
Why don't you use the LX and let her drive the Falcon?