I've seen some outliers, but mostly in terms of promotion velocity. I assume you know about the "bench program"? (Microsoft Fight Club) That could potentially explain it.

I really want to empathize with your underpaid for level statement, I certainly have a pile of stories, I'm just hesitant to tell them because they're rather identifying to anyone who knows me, so you'll have to trust when I say "A good number of us have gotten the short end of one stick or another, often beurocratic or political"