Mrs. Majuki bought a handbag from the Longchamp store at the Pavilion Kuala Lumpur. I've proactively been trying to use mobile payments as much as possible to avoid DCC offers, but this store did not have the option of contactless payments (or simply refused to take them). The DCC offer appeared on a monochrome customer facing signature pad, and the terminal was down on the counter. The cashier helped me select MYR on the signature pad, and the DCC selection was completely within the customer's control if one knew what to look for.
The quoted DCC offer was $126.25 for 485.00 MYR at 3.83%. The posted transaction amount was $117.42, saving $8.83, which would have effectively been a 7.52% surcharge with DCC had I accepted the DCC offer. I don't know how the acquirers calculate the percentage since the exchange rate hasn't changed between the transaction time and the posting date. Chase uses the Visa exchange rate from the posting date of the transaction, the effective percentage could change if there's a material change in the exchange rate between the transaction date and the posting date for the transaction.