Vcds:
Here you go:

Correct Fuel consumption in DIS (C7): (Revised)

[17-Instruments]
[Coding - 07] > [Adaptation - 10]
Scroll down about 20 items in the drop down list until you see something like fuel consumption adaptation - change the value from 100 to higher or lower:
Example - if your DIS is consistently off by 7% to your actual calculated mpg:
You RAISE the number to the percentage if DIS is OVER reporting mpg (i.e. 107)
You LOWER the number to the percentage if DIS is UNDER reporting