Originally Posted by
Pucnit
Fare booking code that the sites could see/use or that AA updated the price and Expedia might not have re-updated their information yet.
I have noticed that for some reason that AA.com doesn't always select the best / available fare code. This can be fixed by putting your itenerary on hold (if all on AA flights) and contact web services.
Add-on to this: I've seen Expedia put up fare rules as if you're getting a certain fare bucket, then you find out half the trip is booked in a lower bucket. I dealt with that when I was doing my plat challenge and points mattered.