There are two different issues here:
- Airplanes that shouldn't appear at KLAX at all (like a SAS Dash), yet they do, it's not a problem of the scenery, it's surely a problem of the Traffic schedule, which is the database that tells what airplanes should depart/arrive at a specific airport
- Airplanes that should appear at KLAX, but park in the wrong places, it's likely due to the fact they have been flagged as GATE only in the atc_parking_type parameter in their aircraft.cfg file and, since KLAX (like JFK too) have most of their parking stands flagged as RAMP, to get rid of default ground vehicles, those airplane will find other spots.
It's probably best to fix the aircraft.cfg and change the line in the aircraft.cfg that reads:
atc_parking_type=GATE
into:
atc_parking_type=GATE,RAMP
This means, those airplane will still PREFER GATE (since it's listed as first), but they will be *allowed* to go to a RAMP, if there's no GATE available.
By changing our AFCAD, the default vehicles would reappear, clashing with our own vehicles, and the same will happen at every airport (not just ours) that use this method so, the best solution is to act on the aircraft.cfg files.