I am sorry that you thought the last bullet point was so confusing that you had to vote the answer as unhelpful. Perhaps the last bullet point should have read: "write down what you did and why and stick it in your tax file for your own records". I did allude to this when I wrote the last line: "But you have your notes in the very unlikely case that anyone ever writes you about this."
P.S. I also corrected the misspelling of "down" (was "done").
