Not sure what the calculation is but, over here in aust.
I get average 5.1-5.6 litres per 100km during commuting (Depending on if I'm late ill give it a bit more)
Freeway at constant 100km/h it drops to 3.5 to 4litres.
This is a F650gs with no bag or anything, just me.. how many miles do you get from full to the reserve light coming on? I get about 220km's - 136miles.