If you're already in the upgrade program from last year, Citizens already has your ss numbers. Only those signing up for the first time had to give it. This year, it seems you can initiate the upgrade program and credit check, etc online, instead of having to do it all in the store.
Correct another credit check will be run upon establishing a new payment plan in store. Just like last years process. The online credit check is only for NEW plan initiates. Existing plan participants have to undergo the whole credit process in store after returning previously financed phone.