As you may notice, you're one of the two or three people in the world who care about the actual number of jobs that Bukowski had, so you figure it out. That's how you become an expert in something. Then in the future, when the 4th or 5th person in the world wants the number, you'll be the go-to guy. Congratulations.
Harrison - and most other academics - have a fatal flaw in all of their work, and that is they take Bukowski's writing at face value. They have to, it's a self-imposed limitation of the footnote crowd. Bukowski's writing is not journalism, it's art, and most of them don't know what to do with art, because it's open to interpretation and not the dry facts that bring them such comfort.