The critical consideration, though, is that the OM loading system protocols must define, adequately, differences between, and procedures for, different models to avoid screw ups. How this might best be done in a matter for the ops management, tech services, and weights engineering folks.
Point is that, if there be no formal protocol to avoid problems, then problems will arise as surely as day follows night.
I can't comment on the Airbus as I have no background, either flying or engineering, with the aircraft. However, when it comes to weights engineering work, an aircraft is an aircraft is an aircraft and differences are unremarkable.