What is your commute route? average speed?
What was the average shown by the car?
Did you use the same pump when re-fueling?
Did the pump wala filled the petrol to full manually or through pump sensor?
Sometimes there can be a difference of how much fuel is "full". So I use to have it filled manually until I can see the petrol and then bumping the car (alto vxr) a couple of times to have the petroll roll into pipes. Not sure same applies with JDMs.
Completing first 500 km on JDM right now and satisfied with the fuel average (Honda N-WGN).
Average speed for my route is around 50 KMH and fuel avg shown by car is 22KML. For a couple of days average speed was 20 KMH and average consumption shown was 16 KML.
Am using PSO hi octane (atlron plus hsd)