These are the pages found in my 2012 manual. IF you have the EVIC it says one thing and actually addresses the MDS, otherwise it only addresses ECO ON/OFF. Since I do not have the EVIC I dont know if my truck is set up to use the MDS function, it does show the ECO ON/OFF but according to the manual that fuel economy based. I do know that the other day I was traveling I-10 east to Houston TX and as long as I was on flat road & in cruise control the ECO ON showed. As soon as I started up any incline, it switched and the ON disappeared. It did the same even if I was not using cruise control. The transmission did not downshift, and the RPM's only minimally decreased.