Have you tried shifting into 6th when the computer suggests? This engine produces peak torque at 1,800 rpm. You won’t lug this engine until you are below 1,500 rpm. Also, a little low-rpm turbo boost is excellent for fuel economy because it eliminates pumping losses. That makes the engine more efficient and improves fuel mileage. If you listen to the computer, you’ll probably get better fuel mileage. Those German engineers know their jobs very well.