Yes, that range looked odd to me at first glance. But your explanation made me realize that I actually use it all over the place. Except on a 1-5 scale. Starting with good enough at 3 (or 0 in this case):

1 = WTF?

2 = Needs Improvement

3 = Good Enough

4 = Better than Good Enough

5 = Almost Perfect

Daniel Kahneman recommends a scale like this for evaluating job candidates across core competencies. It's a surprisingly powerful little heuristic.