I bet they're having some production issues on Breakaway, which means that getting a final 'count' is useless right now. They could wait an extra few days before delivering that info... so hey, why not extend the date to see if we can squeeze any more members in?
That, or they planned the extension all along, just to get all the slackers who procrastinated, then suddenly realized it was too late to sign up. This message thus becomes a sudden reprieve... and they get a quick spike in sales.