I had a similar experience around the same mileage. I chalked it up to the system doing some sort of "break-in" operation. I also got the Banks gauge so I can tell when it's doing a regen. Mileage drops off a TON during the 40 or so miles of a highway regen. Maybe you had a tank with 2 regens? I have seen regens about every 4-500 miles.I have a question, mine is brand new, 1k miles, my first tank I was getting 17-20 mpg on my work commute and my second tank same commute 14-17 mph.
What gives??