I can see making mistakes, we all do. But to mention the theory and explain how to do it several times in the same article, and not once catch the mistake.
Of course the writer obviously doesn't know how to set the valves, which is why it wasn't caught. He got the info from someone and transposed it so now how many guys will go out and adjust their valves this way and have "just a bit" of valve clatter?
Jody