I used a good few tanks of fuel since having my bike set up on the rolling road...... Getting 110miles of mixed riding till the light comes on now. I was getting 90 before the rolling road.
this is the same as I got with the std ECU and baffles fitted.
So now i've got the Full system/power commander and baffles out and a healthy 137bhp its using the same amount of fuel.... so i'd say its using less fuel than when standard.
It'd be interesting to see what you'd get with a standard bike and a power commander to sort out the fueling.