I've just noticed that my rank has gone up. Quite why, I've no idea as I haven't even posted my book yet! All I've done is read a few things, put one book on the shelf and made some comments on the forums. You have a book on your shelf (A Place In Life) by Robert Hartstein that is ranked #98 and has been steadily in the ranks. This coulkd be contributing to your TSR multiple. Also, making comments on books seems to influence the score as well.
Have I misunderstood how the rank is calculated? The FAQ has failed to enlighten me, or I've missed the relevant part.
Many of us have been perplexed by the TSR scores at times. My advice....just go with it.