Okay, I tried to do this with a Cab 1 and a Cab 1L. I was told that you cannot have both systems connected together. It just wont work. I disconnected one of the bases and everything worked as it should have. I was trying to operate 2 TMCC cars at once without having to change the ID's.
I would venture to guess, if you disconnect one of the bases, everything will work as before. It will have to be either a CAB 1/L system or a CAB 2 system you use.