First, if you use other AFCADs, you must be absolutely sure it IS made for FSDT KLAS, not the default. And, if the AFCAD is named differently from the one that comes with FSDT KLAS, you will lose GSX customization for that airport so, it's suggested you use our AFCAD or, at least, if you are sure an alternate AFCAD is in use, it has the same name as the FSDT one.
Also, keep in mind that when you install something like GSX or the Stand-Alone Addon Manager, all FSDT AFCADs for your FSDT installed sceneries will be downloaded and installed automatically so, if you really want to use a different one, you must manually replace it again, and be sure it's named the same as the one that comes with the scenery, otherwise you might have a double AFCAD, which will cause all sort of problems.
Re-test, after you are sure of this. But in general, AI airplanes will park on the *smallest* parking that can take them, but giving preference to those with an atc_airline_code set. But again, if all the best parkings are already filled, they will start to park everywhere.
So, the usual ways to control these assignments, is to check both parking radius and their airline codes with ADE or AFX.
Again, be sure that if you edit something with ADE and compile it back as a .BGL, it must be named as the original AFCAD that comes with KLAS, otherwise you'll lose GSX customization. AND, keep in mind that any edit you do, will be overwritten (a backup WILL be made, though) whenever you reinstall the scenery, GSX or the Stand-Alone Addon Manager.
