well, my stats on the info display are:
16.7 mpg, 34 mph
yours:
21.5 mpg, 31 mph
20.5 mpg, 24 mph
so now what do you deduct?! something wrong w my runner? See where i am getting at it is very hard to reason anything with a single data point.
i would suggest tracking mileage and % city/hwy each day and each fillup stats. once you have enough data to establish a trend, you can actually start to see if you have an issue or not. shoot, collect the numbers and i'll run a graph for you!
i will be posting my 6pt avg plots as 1engineer suggested, pretty cool way of looking at it!
Problem is that I have no historical data to compare to. So I think maybe compare MPH and MPG from other people might help.