I have 2 iPhone 4s phones on unlimited plan. Both eligible for upgrades. Obviously, I can't upgrade without losing my unlimited data plan. I also have 2 dumb phones on the 9.99 family share plan, not eligible for upgrades. Can I pay the $250 early upgrade fee for a dumb phone to get an iPhone 5, then switch the iPhone 5 to my number, then reactivate the dumb phone? All while keeping my unlimited data?