I am Avis Preferred. It appears that the only way to avoid a DCC to your credit card currency is to tell the agent when returning the car. The agent will give you a slip to take to the counter. Hopefully, there is not a long queue. The agent at the counter can manually process the check-out without the dynamic currency conversion and charges you the local currency to let your credit card company to do the conversion. It's a pain and there is no way around it. You just have to allow an extra 15~20 minutes. I have called the Preferred tel. no. to see if they can change my profile and the answer is no. It apparently is the standing policy of Avis.