My daughter dropped her AT&T iPhone 5 in a creek this weekend. I told her that the new models would be announced Sept 9, and the prices of existing models would drop $100 then. I assume if she tried to buy a 5s or 6 before then, she'd have to pay the current pricing. How soon after launch day will she be able to buy a 5s or 6 at an AT&T corporate store and pay the new price? (And walk out with the new phone that day.) Thanks! (She's already eligible for an upgrade, if that matters.)