I pre ordered my 6s, my 4th iphone with them in 5 years, and this is the 3rd iphone on the Next plan. I go with the 20 month plan so I can upgrade it in 12 months so I can get the new phone when it comes out every year. Why does AT&T charge for "estimated" sales tax upfront? Shouldn't the tax be charged monthly with the installment plan? When I was checking out and the site said I was basically given credit for remaining installment payments I was thinking where's my refund for the sales tax I didn't use considering the estimated sales tax is calculated on the full price of the phone that I will not pay when I upgrade. Sure if I finished paying off the 20 payments I would have payed the full price of the phone but I paid 12 payments and am entering a new 20 month agreement that I must pay tax on the full retail price of the phone... Sure, it's under $30 but it's my $30! I'd love to know if AT&T is handing the full sales tax over or is saying "nope look he only made 3/5 of the installment payments before upgrading, so we don't owe tax on the full retail price and pocketing my $30?