Who said that person knew anything about the GSX or A320X code?
Since the ONLY thing that can possibly cause any issue is the CODE (either in GSX or in the A320), by saying there's a problem, it's implied you are saying there's a problem with the code and, again, regardless how experienced anyone can be, he cannot possibly know how the GSX and A320 code works.
Since I obviously know something about the GSX code, I CAN tell you with certainty that
GSX doesn't touch the airplane payload. I think I repeated this several times by now.
I don't know exactly how the A320 code works but, since I'm SURE the GSX code doesn't touch the airplane payload, it's quite clear the only possible reason for any change in payload of the A320 which can be observed in relationship to using GSX, can ONLY happen because the A320 code is REACTING to a GSX operation and, in fact, while I don't know the details, this is exactly what FS Labs is planning to do so, it's all normal but, it might not be completed/finished/debugged. Again, better ask FS Labs about this.
The only thing sure is, again, GSX IS NOT MESSING WITH THE WEIGHT.
I hope GSX v2 is the way to go and it will allow manual pre-setting PAX and Cargo numbers.
As already explained in another thread, GSX will not set the passenger number directly, because this is something that should be done by the airplane itself and, since many 3rd party airplanes already do that, it would be wrong to force users to input the SAME number (possibly making mistakes) in GSX. What would be the point ? Much easier and cleaner if the airplane code will set the GSX variable to the same number of passenger it already has for its own purposes, and GSX will read it, with no user intervention.
In the current version GSX says it loads fixed 170 passengers.
Unless the airplane code uses the GSX variable that sets a precise number of passengers, GSX will estimate the number automatically by dividing the total weight of the payload stations by 220 lbs so, it's not possible it will always say a fixed number of passengers unless, of course, you always load the airplane with the same payload.