The only examples I've encountered of DCC in the Philippines have been at SM Supermarkets. The cashiers tend to hold the device away from you and ask if you want to pay in pesos or USD, so it's very hard to see how bad the rate is. I don't know if they are deliberately being sneaky or are just clueless. From a distance, at an angle, I think it said 5% mark-up, but I can't be sure. (Metro Supermarkets don't do DCC, but they make you sign two receipts as part of some crazy, slow bureaucracy they have going.)