p.s. I just did the same thing with a MOBI of Hume's Treatise of Human Nature, from Project Gutenberg. Converted from MOBI to MOBI, with box checked for Use Author sort for author. "Hume, David" is in the Author sort field. Sent to Kindle. On my Kindle, the book appears under "D."
Perhaps I am asking too much, but I would just like to see books by the same author all in the same place!