I do about 16 miles each way on 90% motorway. If I keep it around 100kph/62mph in eco individual then I average about 38mpg, it regularly peeks to 42mpg but that's cause I'm rolling a lot, eco really can
help if used correctly (i.e, used to maintain momentum and avoid braking when safe/possible)
Long term average is 32mpg, my work commute coupled with some B road fun.
Edit: To the OPs question about 140kph - I find mpg suffers the more you go over 100kph, if I stay at 120kph then I'll see low 30's instead of high 30's