Re: something to consider- The Rock v CM Punk- Royal Rumble....
They use the rematch clause whenever they feel like it. When Punk lost the title at SummerSlam, they only used the rematch thing once the HHH/Nash/Punk feud was over for HIAC. The Rock, himself, never had a rematch after he lost to Lesnar at SummerSlam 2002. Lesnar didn't have a rematch either for his third & final title reign when Eddie Guerrero beat him. There are times when ex-champions ask for a rematch but have to earn it through #1 contender matches/battle royals and so on.
Simple lesson to learn: Don't try to put logic into wrestling.
And on your question, they will NOT do Punk/Rock more than once. That would be a waste considering how limited Rock's appearances are. The WM match for the title will be most likely against Cena. (also a waste but it draws so Vince likes it)