I wanted to follow up on the situation with Avis in Scotland where I was overcharged for a car rental. My Chase statement came out and there is no sign of any currency conversion for the Avis transaction, which means Avis billed me in USD and hence applied DCC.

Since I had the DCC option unselected in my profile ("I choose to have Avis bill all my future rental charges to me in the currency of my Avis profile credit card." was off), the billed amount was incorrect and my dispute was entirely justified. The dispute was resolved by Chase and the difference refunded. My only gripe is that this refund likely came out of Chase's pockets instead of hitting Avis.