How on earth did i miss this thread, great job sharing your experience.
If you use 0w20 in your new alto you will achieve upto 23km/l.
I am probably the first buyer of PKDM Alto in Pakwheels community, the car has given me great local driving avg with AC upto 22km/l with AC and without AC in winters upto 23.50 km/l.
This happens when you use the 0w20 oil, bear in mind suzuki being cheap pour in 10w40 in brand new alto from assembly line, so as soon as you get the car change the engine oil.
I live in urban islamabad where there are signals every 150-200m and theres not much space to cruise around yet this tiny daddu manages 20+ km/l avg even when floored.
I manually calculate everytime i get the car refueled and always buy full tank. Similarly, reset the trip meter on every full tank fuel top up.