This is true of so many other places where the currency is not a strong currency (i.e., YEN, EURO, STERLING to name a few). The problem is that hotels and the travel industry have a rate for local currency against a strong dollar. One of them is the IATA dollar rate. The hotel did charge you at a flat dollar rate US, however the exchange rate is fully variable. Nothing you can do I believe. By the way what will you do with the extra 3% charged by the Credit Card