I'm pretty sure the Deluxe Edition should be $14.95 in your case and that a discount is indeed not being recognized.
Are you trying to order it from
this page or
this one?
For some reason, the first page offers it to me for $49.95, the second one for $14.95...
Anyway, it looks like the issue you're having is similar to the one described in the first post and warrants an e-mail to
support@telltalegames.com.