I finally had a decent go at the issue of 250 Auto fuel economy. Had the 30 000 km (20k miles) service done on my 220d Sport and used the time to do a test run on a base model 250 A. Did both a cruising leg and an urban round in moderate traffic. Cruising at around 60 mph returned 7.0 litres per 100 km (40.4 MPG). Urban returned 9.6 l/100km (29.4 MPG). Good numbers, as I expected. Did the same route with my own car after the service and got 5.8 l/100km (48.7 MPG) cruising and 9.0 l/100km (31.4 MPG) urban.

Since most of my driving is extra-urban cruising, 220d is the one for me. As I expected and have said many times, urban driving is where the 250 A is excellent, both in comfort and in fuel economy.

End note: The base model 250 A costs about the same as the 220d Sport here in Finland. Ended up missing the extra toys. I'm sticking with my car!

PS. Consumption numbers from the BC.

Pretty much identical figures to the ones I get in my IS250 Auto. I am still quite surprised at how easy it is to get 40mpg on a run, even at 75mph plus. I think the high cruising gear in the auto and the aerodynamics help a lot. Obviously, the mpg suffers around town as you are constantly having to accellerate 1600 kg from rest over and over and this brings it down to the 29mpg you recorded.

the question is BC, on 220d is the BC very accurate, while some people say, that on 250 is not so. Can somebody confirm?

It's well optimistic on mine, showing 32.4 mpg overall at present as opposed to the real figure below.