My previous A6, 1.9tdi 130 had no dis and I always worked on a figure of £10 of fuel would do me about 75-80 miles.
I now have a 2.5 tdi 180Q sport and am getting 100 miles to the same £10 of fuel.
Strange as I expected the consumption to go down. Based on this I have calcuted that my average consumption is 42 based on 93p per litre.
My DIS shows an average consumption of 31mpg.
Now I wasnt expecting it to be accurate but this is miles out.
How does you DIS compare to you manual calculations?