How does GSX decide which particular type of air stair to deploy ?
As for any other vehicle, it looks for all possible candidates that best matches the ICAO code of the airport and the atc_parking_codes of the parking in the scenery AFCAD. Then, it throws away all that have excluding conditions like (in case of stairs) airplane door's height being in a certain range depending on the model reach and finally, for all candidates that matches all conditions for both liveries and models constraints, it selects at random.
Which means, seeing different models of stairs without changing anything, it's perfectly normal, if more than one matches all conditions.
