Word 2007 The Missing Manual - cost of PDF

I note that the O'Reilly Store sells "Word 2007 The Missing Manual" combined Print+PDF for $9 more than the Print book price. I have purchased a Print copy of the book from my local bookstore. For me to now purchase the PDF I would have to pay $23.99 which is almost as much as the full Print price. Can the O'Reilly Store management consider offering a more substantial discount on the PDF price to purchasers of the Print book who can provide evidence of purchase (say, by emailing of purchase receipt)?
Thanks