Interesting, and you make a good point about true accuracy of fuel consumption
I have often wondered about this (and don't have a sat-nav to check) - if a speedo is reading, say, 10% high, does it follow that the odometer is also overstating by 10%, ie a bike showing 20,000 miles may only have covered 18,000?
I also wonder where all my fuel is going - I have a pretty easy commute (65% near empty dual carriageway, a good 20% country roads and less than 15% unsnarled urban routes), I don't hang about but don't recall ever hitting the red-line, never mind the limiter (has it got one?!), in fact I rarely stray over 5k rpm (though I might be there or thereabouts most of the time....), yet I don't think I've ever achieved more than 50mpg. Standard pipes, K&N filter, air-box mod (bolt up the rubber hose method). I generally run on premium unleaded, too, a habit going back to my days in Australia when regular meant 91RON, their p*ss-weak beer would have made a bike run better.....