Too many threads on this and absolutely, positively no correct answers. Maybe EA changes the reqs. week by week to keep us all guessing.
Anyway from my personal experience, the only semi-evidence I can figure is that I got it immediately after I played for 24 hrs. as MEC. This seems logical to me. Also, whoever said that there was no signal in round is right, I just looked at BFHQ and there it was and I had about 24 hrs and 8 minutes as MEC.
Either way, some of these "confirmed" requirements are ridiculous folks. I think we should all just give up on this one and focus on having fun and getting other awards. This will come in time.
Plus, I'm starting to think that a lot of the "confirmed" reqs. are wrong based on how many people are getting medals. They can't all be glitches. Also, I don't know about everyone else, but I always doubted that EA would make an award with a req. like 4000 global hrs. That's absurd. No one would get to that except the very few top players who have no lives. They wouldn't waste the time, money or effort to have a graphics designer create a beautiful medal only so 25 people in the world could get it. But whatever, I'm sick of this subject. It's been rehashed a million times.