After finishing first or second in 3/4 of my first $3 CC tournaments, I used to have ROI of well over 1,000% for that level.
It's obviously dropped significantly since then.
Basically, 120% is probably unsustainable in the long run. While I don't have a lot to look at, SharkScope has you at -52% for S&G's, and looking at the Official Poker Rankings link, if one thing went wrong early in that April 4th game (which accounts for more than half your profits) you'd be nowhere near the 120% mark.
You do seem to be a winning player, and if you're doing even better in private tournaments then stick with it.
For example, tatta was the #1 earner in the <$100 HU games in 1997, but had a substantially lower ROI. Consistency over the long haul is what we're looking for, (not that you're not doing very well!):
Note: tatta has a 14% ROI now.