Strange that you were payload optimized going eastbound. I've only heard of that being an issue westbound on MD-90 flights from MSP to the West coast. It didn't look like your flight had much of a tailwind to work with, but you weren't facing a wind or having to avoid weather either. It also appears to have left with nearly all seats filled. Could have been lots of reasons I guess. Might have been cargo that had to fly. Could have been a mechanical issue that created a fuel burn penalty. Could have been fuel for holding at MSP due to the foggy day we had. Strange. Still, that's one reason I avoid those MD-90s to California. It doesn't take much to create weight restrictions.