My 2cyl ER6F averaged between 4.0 and 4.5l/100km around town and usually no more then 4.0l/100km when traveling, loaded
up, usually between 100 and 110 like you wrote above. Lower displacement 4 cyl bikes can be thirsty (like the fazer 600,
hornet 600 etc) since they got no torque down low.
To chug along you don't need it. FZ600S can do <4l/100 kms too.
If you drive any 600 like semi-tard and carelessly, it will consume in vicinity of 5.5 l/100 km, including all out on highways.
My P250S currently consumes >5 l/100 km when driving quite carefully, 60-80 km/h, no higway. It used to hover at -25% off that, have no idea what happened.