Nice job! Now google: "average"
Bit harsh with the dig at the end; he did a good job and actually highlights a lot of peoples misconceptions.
Long-term losses are another issue and are usually a problem with the miner actually submitting shares and/or invalid ones.
Maybe it's because of me. The PS part might made him think I was being sacrastic. Which was not my intention. I was trying to point what to search in case anyone would like to know more.
English isn't my first language. My apology.