Just recently purchased new XC 90, 5 cyl. First 1300 miles all local driving. Average mileage 16-17 mpg. Went on 3600 plus mile vacation. Computer said 19.4 avg mpg. Old fashion hand calc = 20.46. Kept trac of each tank. Hand calc always more. Some time as much as 2.4 mpg ?? Two fills of 22-23 mph. Drove 72 mph to 87 mph depending on posted limit. I have had 2 previous XC 70,s purchased new, both 5 cyl. Computer calc and hand calc were always nearly the same. So far it looks like XC 90 posted sticker mileage is going to be pretty close if you go by manual/hand calc. So far I really like the XC 90.