I've seen other confused by the MS link setting, and now I am too.
I set it for MS link. During recording, and upon playback, I hear two separate mono mics. It's not encoding for either live monitoring purposes or playback. If it's a two step process, or there's another setting that locks this option out, I'm not finding it on the unit or seeing it on the manual.
I usually don't want to use this setting, preferring to encode in post, but at times I want access. I'd particularly like access for live monitoring checks, maybe to do a test with it on to see what I'm getting, then switch it off for most recording.