Here's another "From the WTF Files" with my 2.0t:
I just did another tank (420 miles) with about 60% highway cruising at 65 - 70 mph and the rest city. The overly optimistic trip/mpg computer ranged anywhere from 38mpg after I filled up on November 26 (cruising down I-40E at 70mph) to around 28mpg when I was driving around in the city.
Finally, the computer had settled in on 30.1 mpg by the time I pulled into the gas station. I filled up the tank, did the calculations and actually got 25.94mpg.