There are a lot of Macmillan books with an agency price of $7.99 that are discounted to $6.90 at Diesel. If Diesel can discount agency prices in the US then why can't Kobo?
There is no agency pricing in some countries, and yet Kobo discount codes don't work on some publisher's books in those countries. E.g. Orion (Hachette) books don't allow discounts in New Zealand. But discounts do work on Orion books in the US, e.g.
http://www.kobobooks.com/ebook/The-B...UXQ/page1.html.
It makes me think it has nothing to do with agency pricing, just that some publishers arbirarily refuse to allow Kobo to discount their books in some countries, just as they charge different prices in different countries, or have special offers in some countries and not others.