Hmmm, yeah - can't fault your math. Maybe my foot was a bit too heavy with my CRD. If I got out on the road, got it up to 60 mph or so, re-set the computer, and stayed at that speed for 10 or 12 miles, I'd see 26 - 26.5 mpg. Real world, day-to-day, though, I was getting closer to 20 for combined...