My wife and i currently each have an iPhone 4 on AT&T. Would the following plan work: -She would order a iPhone 5 (32gb) with the uncarrier $50 a month plan. -I would get a pre-paid $30 a month 4G plan sim from T-Mobile (which is only for new activations, so i assume it means only people who have never had T-Mobile before?) -If the coverage was good enough on the iPhone 5 during the first month, she would pay off the remainder of the balance, close the $50 a month account and then use the $30 a month prepaid sim in the iPhone 5. -Then would transfer over her number from her AT&T iPhone 4. Would it work? Ultimately, we'd like to get her phone on the $30 a month plan, but first we'd like to make sure the T-Mobile coverage was fine around town before porting her number over and losing her old cheap (but very limited) data plan with AT&T. Thanks in advance!