Only if you run the service as two branches, one to Forest Hill, the other to Bell Green. The existing services would then have to be split between those two stations in the same way the current ELL trains are with West Croydon and Crystal Palace.
It would mean less trains to Forest Hill on the DLR if that happened running about the same frequency as the current 185 bus service which might lessen the benefits of having a DLR train every 5 mins to Catford.