I don't think that this is a 15 dollar add on, I think that it's a 5 dollar add on.
I've been thinking a lot about this. When I set this add on to free people start downloading it like hotcakes, when it is 15 dollars nearly nobody buys it. I'm thinking of withdrawing it from the marketplace and selling it here for an unlimited license for 5 dollars with limited support. If people think that this is something they would be interested in, please leave a comment below and let me know how you feel about it.
For reference here is the add on's marketplace page and here is my writeup on the add on.