if I am in chaseplane at Charlotte...It lists 2 (36R) and (2) 18R and no 36C but in the selection for Charlotte there is only one of each runway and there is a 36C.
This clearly indicates your problem doesn't have anything to do with GSX, which is confused exactly as Chaseplane is by the real cause of the problem, which is an AFCAD coming from another scenery in conflict.
When the gate positions don't match, it's usually a problem caused by another AFCAD in conflict. The most common cause of conflicts are those AFCAD supplied with AI traffic products, which are supposed to be used only if you use the default scenery, but must be removed if you have an addon.
You can use the free Simple Airport Scanner utility to search for duplicates AFCAD:
http://www.scruffyduck.org/simple-airport-scanner/4584282795Or check the name of the AFCAD used by GSX in the parking customization page.