Originally Posted by
percysmith
But be careful - your extra ratio's gonna get rounded up to nearest HK$100 per transaction (this point confirmed with CS). If you run 15 transactions of HK$750 in your US trip, for instance, you'll be rounded down by 7.5 DB$ or 156 miles for instance. So the number of miles you earn will be (750 x 15)/2.18 - 156 = 5,005 miles, which equates to (750 x 15)/5,005 = $2.25/mile earn rate.
This is still a far better earn rate than any other card I have although I need to compare my forthcoming BankComm CUP card. It has no foreign transaction fee if I remember correctly and pays HK$4/mile. Just need to do the math.