Well considering I've owned the truck for 28,000 km and have played with the ECO/MDS off and on and hate it with a passion, I will lay a years wages on that's how it works in 5th gens. It's absolutely the same thing; ECO = MDS. I have never once seen a case where MDS was active without ECO, or ECO light appearing the exact second MDS kicks in. I've watched the system like a hawk, in an attempt to "learn to like it", but I always run with it off. Every few weeks I'll try again and the ECO light flickers in and out for about 10 minutes until I get annoyed with it and shut it off. ECO light won't appear for another 3 - 4 weeks. Not exaggerating in the slightest, every word there is true.
As for this being a 4th gen thread; fair enough, I did not catch that since I never actually read the forum by going to specific sections, I just use the "new posts" page.