I rewatched the keynote last night and they were presented in this same order as well then. I'm with the OP I wouldn't be surprised if the sport was actually right in the middle. I'm sure with the right band combo the regular could probably out price the sport.... But I think if we look at just the cheapest versions of each, the sport will NOT be the cheapest.
Sapphire Glass and Stainless Steels costs more than Aluminum and regular Glass. The Sport Watch will be the cheapest.
Also watch the interview Re/Code had with Joswiak. He did't dispute Walt when they mentioned the Sports Watch was the cheapest. He also said "Not everyone has to buy the Rose Gold Model" which also implies that will be the most expensive.