DVD set question

Hi
I was happy to know this show would come out on DVD! Since no local store would carry it, I knew I would have to order it online. But instead of amazon or bn.com, I chose ebay. Upon receiving the set, I notice a few things: episodes on both sides of the discs, and the 'thin' DVD case has an empty space since there are 3 and not 4 discs in the set. Was this the same for everybody else? I just want to make sure, that's all.
Thanks