Lindsy-
I have 2 cards tied to UA thru First Usa and they have been and I believ remain subject only to the 1% currency fee that Visa & MC lay on everything. In other words, First USA does not add anything more-my guess is UA has this in the contract.
Your post isn't crystal clear-it mentions a UA tied card but it seems after several readings that you in fcat used a BA tied card, and that First USA said that the BA card had a !5 fee but you got charged more.
I bet whoever you called and had email from was thinking of UA even though you have BA. And my guess is you can compain enough to get the excess removed for the recent charges that had a higher fee, since you have a valid email saying that was the fee. A service agreement would be better but they can't expect you to hire a lawyer to question their written advice.
The day they increase the UA cards above 1% is the day I take my considerable business to another card-and not just for overseas charges; I mean for everything.