So I've had my Nexus 5 since August of last year. I have gotten my balance down to -167. If I divide that by 24 (which would essentially extend my time with the phone to two years starting from the switch) I would only have a 7/month tab. However I would probably have to pay 15 if I have to consider what my phone cost initially which would have been tab medium. So if I switch to the new plans, is it based on my current balance or the original price of the phone?