My mehran 2010 is doing 23 km,s on per kg of CNG on long without A/C while in city 20km,s.And on petrol 17-18km,s on long and 15km,s in city with out A/C.While if the cylinder filled at normal pressure of 220 then it does 25 km,s also.I think its the maximum average of mehran.and on A/C this average has a little bit difference of 2-3 km,s only.The average also depends upon your engine condition also.as it is a 2003 model.In my old 90 model mehran it gives only 18 km,s per kg.
MR.Habibalam you are comparing mehrans average with the car having some 2000 cc engine even my jimny does 18 km,s in 1 kg and 12 km in 1 litre having 1300 cc engine.
bro check up your car.