Yes, you should to reset your PBX to factory defaults and program it again.
About backup uploading - AFAIK you can't use a backup, because it contans information about System Capacity Type.
It is better to create a new configuration file in offline mode by using NS unified WEB MC, then reset your PBX, perform a first start procedure with choosing new Capacity Mode during it and then restore PBX setting with newly created config file.