Comgratulations to your DS!!!
(sorry, forgot his name
)
Our schools used to participate in a similar program where they got a coupon for a free Personal Pan Pizza & drink of choice from Pizza Hut. Anyone who read the required number of books got the coupon. No one got anything extra for reading above & beyond the required number.
I don't know why they no longer participate. I had forgotten about it until I read your post.