The uploader don't get points when one of his torrents is made freelecch. My guess is that the "lost" points were given by "unknown" members, means members who's account got deleted from the data base and therefore their name (with the points given) can't be shown.
Thanks Popper for the explanation… I think its clear now 😉
Transmission was very popular among Mac (and GNU/Linux) users, but now that a well working version of µTorrent exists for Mac, it became the most popular client for Mac users, too.