Ok, moving on Valvoline Durablend to M1 5W30 gave me a huge MPG difference.
Valvoline : 38 litres = 390 KM
M1 : 38 litres 510 KM
This was typical 2 weeks run, no different driving styles etc.
So i must admit I will save the cost difference in a month or two.
Is M1 5W30 suitable for high RPM engines?