<p>Generally, it’s for people who are absolutely sure they got an easy 5 at the high end of the scale and end up with something like a 1 (this might be a bit of an exaggeration). However, you expected a 4 and got a 3, which might mean just a difference of a single point, who knows. I wouldn’t waste my money; if you’re absolutely set on it, then go ahead, but I don’t think anything will happen; still, it’s just $15, right?</p>