This wouldn't surprise me because I had no problem at all moving from the original iPhone to the iPhone 3G at the upgrade price. I even got Apple to give me another 3G at upgrade price when I dropped mine and broke it.
For the 3GS and 4S, I used my girlfriends upgrade, and gave her my old iPhone. So I did not bother to try to upgrade my own account.
In the early iphone days they let people upgrade for the $199 price, but stopped doing that with the 4 unless you are really close to an upgrade. I have another year to go, so no way they will give me the $199 price