Those 48-hours are real-time and not in-game. So if you start midday on Saturday your game time runs out midday on Monday, no matter how you've spent it. Still, you can't argue with free. Well, you can, but there are better things to argue with, like paper cuts and the necessity of shaving. Finally, if you did take up the first Game Time offer back in June, you won't be able to take part this time.
The news follows EA's unveiling of the third DLC pack, IMC Rising, which drops sometime this fall. We haven't yet decided if IMC Rising sounds more like a bank or a hip-hop group.