Thanks guv1976. Currency fluctuation sounded like a good theory, but as you pointed out a fluctuation resulting in exactly $10/ticket for both itineraries purchased and cancelled at different times would be odd.
Plus it looks like the fluctuation between purchase and refund dates would have actually resulted in a higher USD refund by a few dollars. I don't want that, I just want what I paid back since it was marketed as refundable and the fare rules don't specify any cancelation fees, at least as far as I can tell.

Any other ideas that would justify AA keeping $10 per ticket?

Thanks again.