I don't think that's what Mo means. I believe you may have misinterpreted him, I think he means to say he doesn't want to compete when he is feeling only 80-90%. Not as a percentage of his chance to win, but of how his body feels at the time. By feeling 100%, he would be feeling ready to race, but by feeling 80-90%, he doesn't want to race because he is not feeling his best and feels he wouldn't be able to compete at his best. Easy mistake to interpret, but very different from what I believe he was saying.