AI aircraft with no parking codes in the fltsim.x section of the aircraft.cfg file will be assigned to parking spots with no parking codes first.
If the atc_parking_types=GATE the aircraft will be assigned to uncoded GATE x spots before beings assigned to GATE A x spots. There is no priority between letters - GATE A 23 and GATE Z 1 will have the same priority if they are the same size.
Only after all the uncoded spots have been filled will AI aircraft be assigned to parking spots with parking codes that do not match the AI aircraft.
@ PawPaw's house - near KADS, Addison, Texas, USA