Ok, just done with a full tank . I have calculated and approx it is giving 13.4 Km/L (City)
Not sure if it is good or not. My Santro use to give 9.3 Km/L (City)
My Santro tank usually filled up at 2000 PKR, and the full tank gave me 210KM
Alto Tank filled up at 2000 as well and the full tank gave me 350 KM.
Not sure if keeping 660 is worth ?