Before leaving Karachi while driving in Karachi my average driving on Shara-e-Faisal was giving me around 45 km / L. In the city I was still getting 38 km / L
During the first part of my trip where I drove mostly on flat surfaces it was approximately 42-43 km/L due to extra weight. But as I drove through steep hills and mountains it was around 38 km/L and in the much steeper mountains it may have been a even less.
But I guess you could average that out to 40 Km / L
My way to check for fuel efficiency was to keep an eye on my odometer and see that when I am doing approximately 6,000 RPM my speed should be close to 80 kms or just under. That was my best way of calculating it. I noticed at one time that I was getting only 75 kms at 6,000 RPM and realized something was wrong. I stopped first to check engine oil level from the side round hole and it was fine and then looked for a puncture shop, and after checking the rear tire pressure realized that it was below the ideal pressure and only 33 psi which we brought up to 40 or was it 45 psi and then when I got back on the highway the reading on the gages was back to normal.
On the other hand when I went at 90 kms I knew the fuel economy would drop substantially. Due to high wind pressure I was using up more fuel but that was only for a few kms when I was enjoying the ride and nothing to worry about if only for a short distance.