85mpg while listening to Basshuner "All I ever wanted" would be a hard thing to do - ahah..
I get around high sixtys when I do a long journey, mostly in cruise at about 70~ in my avant ultra (190)
There were large stretches of road works restricted to 50mph. Even so, was a little surprised to see that figure.
I don't think there is much difference between dynamic and efficiency modes when you drive on motorways. The biggest difference you will see is in urban driving where you constantly changing gears and in dynamic it reves up higher and changes gears later. While cruising on motorways the rpm at lets say at 70mph is the same in both modes. At least these are my observations.
I know from my A6 efficiency mode does make a big difference. It restricts the aircon and also strangles the throttle response somewhat, in order to improve economy.I thought the same until I had a 70 mile commute a couple days a week and found that versus Auto and Comfort, the Efficiency setting actually gave me about 10-15% better mpg for the same dual carriageway drive. I don't know why because it didn't seem to have anything to do with the revs specifically as they're generally the same for those settings... Give it a try next time you do identical journeys and see what happens.
Mine coasts in auto...I thought Efficiency mode also enabled coasting (in autos) which may/may not help depending on driving conditions?
"Although it won’t coast all the time, it seems to pick and choose when it wants to do it."