I just did one for Drizzt, and I got 20% - seriously, that's all?? This man is the epitome of FR Gary Stue-dom!! He even has purple eyes, ffs!! (and they're described as "violet orbs")
The test is flawed, though - for a start, there's no option for your character having never fallen in love, the age questions don't take account of different races (elves, for example - they're all above 40 but that doesn't necssaily de-suify them), and there aren't enough questions about combat prowess, which is a major Sue/Stu defining factor.
As for being a self-insert...does that really matter? I think it's less about where the character comes from, and more about what he does. A well written, believable, and suitably flawed self insert is surely better than am awesomely powerful and flawless character who isn't a self insert.