The conversations at United are twofold:
1. In the ear of DoT trying to figure out if they can get out of honoring these and
2. Legal looking over the liability clause of the contract UA has with whatever exchange rate provider they use (that apparently the IATA uses). If they can go after this 3rd party to make them whole, they'll honor the heck out of them as a "goodwill gesture" and get the exchange rate provider to make up the difference.