Based on how you are able to get that mpg on your current ride, I'd say it is possible. Not by me though as I've always had a lead-foot and I cannot avoid the temptation to put her in sport and sport+ mode to listen to that sweet exhaust note.
So if you have enough discipline to drive a 35is fuel-efficiently (which I believe takes a lot/lot/lot of discipline - probably more than I have =) ) - I would say it is possible to get 24+mpg. In comfort mode the engine runs through DCT gearing so quick and smoothly with plenty of low end torque, you find yourself in D7 in no time at all at cruising speeds. I typically average 17mpg on my short commute and that is city drive and as I said - I have a lead-foot and like to hear that exhaust in sport & sport+ mode a lot!