I currently have an iPhone with no service (bought it used). I have been considering signing up with AT&T for month-to-month service ($69.99 level), but I'm a bit curious about what I'll be able to do when the new iPhone comes out this summer (supposedly). If I'm paying for month-to-month service on my current iPhone, will I still be able to get the discount on the new iPhone if I sign up for a 2-year contract at that time?