I totally agree with the "two answers".
Your mileage with those two conditions is right around the ballpark. I have been getting constant 13.5 though with 75-25 City/Highway driving.
I was in Melbourne last week and did a 750 km run with one full tank (I use only CALTEX 91 ULP) and ended with a 8.0 l/100kms. Five passengers and a full loaded trunk.
I did change one thing in the recent past and now my city driving also gives me 12.5-12.8 l/100kms. My dealer has started using RAPSOL (sounds like a medicine) instead of Valvoline. I am not sure if this is to blame for the increase in mileage.
Overall, I am happy with my Grande 4x4. 8.0 is a great figure with a vehicle that size. Do NOT use that Ethanol garbage... It will decrease mileage for sure. Not enough energy per volume.
