Salam
on my last fill I got 12.5 km/l. all in city with 20% AC. speed never gone abbove 60 due to crowded roads. average speed would be 40 with frequent braking and acceleration.
Few weeks back went to Jhelum and back to Islamabad on GT road and got an average of ~16km/l.
Regarding CNG well I heard form 2 guys using CNG with Steermatic and are completely satisfied wih it. One of them claimed that he went to Lahore on Motorway for only 400 Rs.