Are you talking about the ECO display. That by itself doesn't mean it is in MDS mode. I can tell when mine 2011 goes into MDS which is extremely rare. When it happens it is always on a flat no head wind interstate with the cruise set, and you can tell because you will get a harmonic vibration in the steering wheel.
It’s been a couple of years, since I was in one. I thought I had to go into one of the menu’s. The “ECO” flashes regardless of what menu screen you use. Ours were the ”police”/“special service” whatever they were called. They didn’t have the same menus as the regular trucks, which we also had a few of.