They will issue a 1099, if they haven't done so already, and whatever they list the value is , well, that's the value.

I think one of the things that will be a bit difficult to change is that you said the value was in the rules, which you agreed to before entering, so you are probably stuck with them.

That's what AA sells the miles for according to the posts here, so that's probably how they came on the value.

I once won a mickey mouse tote bag from disney in a stupid sweepstakes, they actually 1099'd me for the $15 value of the bag, and it was enough to bounce me into the next tax level, so I had to pay an additional $18 in tax. I still have the bag someplace.