Ah, so it's that simple :p
It usually is with Quagmire
The only thing close to that I can think of is that THPSHD, being a Summer of Arcade title, might have pricing guidelines to follow as well (I don't think any SoA title has been over $15). Of course, Rock Band Blitz isn't part of the Summer of Arcade, so--presuming there's a price ceiling for those titles--it's absolutely irrelevant to Rock Band Blitz's pricing.
Not sure why there are export only options since that isn't going to be an option for this game. I'm thinking it will be $20 though. A game that is backwards compatible with all RB DLC should cost at least that much, and, as mentioned is still a better deal than the track packs.
I've got mail, would that be a better offer?