The fuel consumption display on my X5 seems to be quite inaccurate. I filled the tank, reset the trip computer and then drove around for a few hundred kilometers, then filled up again. The fuel consumption according to the trip computer had averaged 12.2L/100km, but when I work out how much it took to refill and the kilometers I travelled, it was actually more like 13.5L/100km.
Are these normally that inaccurate, or could there be something wrong?