@indigograce – I wouldn’t get too hung up on it. I’m pretty sure the quiz even says somewhere on there that there are plenty of characters who wouldn’t be considered Mary Sues/Gary Stu’s but score really high anyway.
I think it’s just a good double-check to make sure our characters believable. Real people with real flaws (being endearingly clumsy *ahem…Bella Swan* with no other negative traits does NOT count!) 🙂
Sometimes, without even realizing it, it’s easy to create MC’s that are such speshial snowflakes that all the other characters just sit around bowing to their awesomeness because they have no hope of competing with them, so things like this can sometimes be helpful in showing the error of our ways. Or, they can just be good for a few laughs. 😉