I got 32.2 on my last tank. This is the first time the DIC was pessimistic, it showed 30.5. It's usually two to three MPG optimistic.
I overfilled the last tank and the tank threw up (gas spill), so I'm not sure how accurate this is.
I did run the ECO button, the first time I've done that since it was new. Then, it seemed to make little difference. Perhaps the critter had to learn my driving habits. It short-shifts noticeably now. I see from the manual that if you WFO or the cruise control needs more power, the computer will override the ECO.
Stay posted for more details over the next couple of tanks. If this proves real, it's very good news to me.