He keeps on saying that Princeton's students are geniuses... this might be the answer
Anyway, I study with thoses courses myself, and I have given up understanding his notation in details, almost from the beginning. Nevertheless, I know that if I had made the effort to understand it thoroughly, I would know be able to predict many forms and endings, which I can not now, because I did not care to spend time with that.
For example, I am sloppy when it comes to guess if some feminine adjectives in the genitive case should end with ой or ей, or stuff like that.
Whereas I know his method makes it almost infallible.