Bandai Packages DVD And UMD In Same Box, Charges More For It

GamesIndustry.biz has the story that Bandai is planning to release their new anime series, Eureka 7, in Japan on both DVD and UMD (UMD being the PlayStation Portable's media format).  The odd thing is that they will be packaging both DVD and UMD in the same box which, while convenient, will cost you more than if you just bought the DVD and UMD separately in their own cases.  What possible motivation is there for consumers to buy the bundle version for more money than the individual versions cost?  I fail to see the logic in this.  If Sony and their various media partners want to push the UMD format into the hearts of their fans they really should charge a little less for the bundle, not more.