1) Model: Toyota VIOS 2006
2) Petrol Used: Shell Vpower
3) Engine Oil Used: Toyota Fully Syn
4) Fuel Consumption: 11km/l average
5) Driving Condition: 100% city
6) Average Speed: ~100KM/h
7) Average RPM: 2.5k (engine sluggish at <2k rpm)
8) Latest mileage: >25000 KM
9) Modification: Stock
10) Air-cond usage: 90%

1) Model : Honda Accord 2.4
2) Petrol Used : Shell RON95
3) Engine Oil Used : Honda Full Synthetic
4) Fuel Consumption 12KM/litre
5) Driving Condition : Highway (60%) and congestion (40%)
6) Average Speed/Max rpm : 80-120km/h

That's not right. My car is a local made CKD, and using RON95 is not a problem. I have updated the latest stat...

1) Model : Honda Accord 2.4
2) Petrol Used : Caltex RON95
3) Engine Oil Used : Honda Full Synthetic
4) Fuel Consumption 15.5KM/litre
5) Driving Condition : Highway (60%) and congestion (40%)
6) Average Speed/Max rpm : 80-120km/h

1) Model : Honda Accord 2.4
2) Petrol Used : Caltex RON97
3) Engine Oil Used : Honda Full Synthetic
4) Fuel Consumption 16.5KM/litre
5) Driving Condition : Highway (60%) and congestion (40%)
6) Average Speed/Max rpm : 80-120km/h

On speed constant, I am getting slightly better reading using Caltex RON95 to Shell RON95. If I use Caltex RON97, I am getting slighly better reading than Caltex RON95.

It's because of your fuel - Shell RON95 is a NO.

It's the BRAND of the fuel my friend. Try changing to other brand BHP or CALTEX with RON95.