In addition to what Csturdiv stated, you may want to see if the AFCADs use radius measurements as opposed to ICAO coding. What I mean by this is the AFCAD author may change the radius of a gate such that a specific plane parks there and lines up with the jetway correctly. An example would be changing the radius of a gate for an MD
-80 as opposed to a 737-700. When you use the default "small" gate, both aircraft are able to park there, but because of the length of the MD
-80, it juts forward from the jetway moreso than the 737-700. The radius adjustments make it such that an MD
-80 is the only aircraft to park at the gate, leaving the 737-700 to find another gate. There's a whole list of radius adjustments for specific aircraft at ProjectAI.com.
Personally, I'm not a big fan of radius adjustments. I'd prefer using the default gate settings and accepting that the MD
-80 may look unusual if its not lined up perfectly to the jetway. The radius adjustments are tedious and can get complicated if you have many types of aircraft at an airport.
One final item, for the Expressjet ERJs, if you do plan on using the default, make sure you use "Ramp GA
Large" for the ERJs.