That's what I thought as well and I am surprised nobody else seems to have picked up on it.
Personally, my purchases go down by more than 30%, as I end up adding the song to my wishlist to see if I can get a better deal on Amazon or Lala, but never get around to checking it out, so they keep staying on my wishlist.
Some people don't know how to use percentages properly. In most cases you just can't add them together.