So you get a new iPhone for $27 a month. After a year you have spent $324. You want the new iPhone 6, so you have to continue spending $27 a month or whatever it is, however, you have 8 months left on the iPhone 5S, so you owe $216 when you get your 6 to buy out the rest of your 5S upgrade pricing. Do you even get any $$ for your old iPhone 5S when you shell out the $216 to be able to start paying $27 a month again.
I don't understand the owe $216 part mentality. Sure, you technically owe that with 8 months left, but that's waived when you give them your old iPhone 5s and they hand you a 6, starting a new 20month plan.
You've gone from $199 every other year to $27 a month every month plus $216 each year to buy out your payment plan. Across 4 years you could have the iPhone 5S and 6S for $199 each or $400, or you could have the 5S, 6, 6S, and 7 for $2,160.00 !!
True, you end up paying more in one year, $324, compared to the $199 down payment. But again, you don't buy out your plan at 12 months, you just give them the old phone, walk out with a 6 and continue paying the $27 a month.
So $2160 seems way off. At the "beginning" of the 4th year, 36months paid,
I'd have exactly handed AT&T $972 and gone through a 5s, 6, 6s and now have an new iPhone 7 in my hands, walking out with another 20 month plan. That's over double the $400 if you just got two phones over 4 years at $199, but I'd have had double the phones.
Something about that just doesn't seem right for any consumer.
If I sell my iPhone 5, I can get $400-500 for it. A new one would cost me $850 (64GB model). That means last year I spent $400 for it, I could get that back and maybe then some. I'd have to pay $850 for a new one at the same size. And next year be able to sell that for $400-500 and get an iPhone 6 for $400. So it would cost me $650 - $850 total for a new iPhone each year for 3 years. That's $215-$285 per year for a 64GB model each year. And I don't have to sell early. I can sell it after I acquire my new phone or at the same time.
Based off my calculations above, it's not really worth it to me to go through all that extra hassle with selling phones and large upfront payments. At 3 years, when I get the iPhone 6s in my hands, I'd have paid just $648 (after 24 payments, excluding taxes), which is at the bottom of your plan's estimate. Though, my calculations are for a 16gb, but I'm sure even with a 64gb, it still might fall within your 650-850 range, and without all the hassle. Also, the $36 activation fee is waived automatically with Next, while the other ways you have to do later through chat or calling them, and usually everyone has success.
The "Next" way will obviously be more costly as time goes one, but the extra cost is worth it to me for the convenience.
Also, I made the mistake of going form an iPhone 4 to a Galaxy Note 1 that's no longer worth much and regret getting. It's been a nightmare and torture waiting for my upgrade, especially with Androids. For the iPhone, they usually hold up well, especially in the non "s" cycle, where it's a whole new phone. Starting with the 5s, I'd love to be able to get a 6 a year from now, as it may be a whole new refresh and larger screen.