There are four mode doors; one defrost/demist door, one floor door and two panel doors. All mode doors are driven by one mode actuator that is attached to a mode cam. Each panel door is driven via a linkage to the panel door shaft. The panel door shaft is connected to two panel levers that are interconnected and driven by the mode cam. The floor door is driven by a floor door shaft that is attached to a lever that is driven by the mode cam. The defrost door has a lever that is connected to the mode cam with a linkage. All mode doors are serviced as part of the HVAC housing and are not available as separate components.
The only way to run a calibration procedure is with the dealers scan tool.
Since there is only one actuator operating all of the doors, there is either an issue with the lever and linkage for the defrost door, or the door itself may be broken away from its pivot.
Replacing the switch assembly won't have any affect on this and I'm doubting a calibration would either......since everything else seems to be working ok......but you never know.
I'd suggest you let the dealer try a calibration just to rule that out, otherwise I suspect the dash may need to removed to gain access to the heater box.
If the dash has to come out to repair this you are looking at about 6 hours labor plus whatever parts are required.