For those of us who bought the Journey Collector's Edition for $15 (instead of buying Journey on PSN for $7.35)...

Does anyone know if either (1) the included free month of Playstation Plus (which I thought I read somewhere expires on 12/31/2012) will stack onto an account with an existing Playstation Plus subscription or (2) will the free month code inside of Journey never actually expire (just as most Xbox Live codes with expiration dates never expire)?