I have had very simular results with our BFII xr6 turbo, the trip computer is pesimistic, the best I can manage on the computer is about 10.2 outside the city, but work it out the old fashioned way and its usually in the low 8s Interesting to note too that my missus has noted that on the same work comute for 5 days it seems to use within a litre per week of her subaru liberty RX 2.5 auto that we just got rid of, so the XR is cheaper to own and run because it dosent need fixing.....ever, unlike the subaru.