Board Thread:News and Announcements/@comment-1739368-20151024224712/@comment-1739368-20151223015742

They sell 15,000 or less per volume, not the entire thing. Any series that sells over 10k per bd is considered extremely successful. Likely reasons for the drop:
 * 1) People bought less per volume because there were more volumes to buy. Overall, the SC bd's still outsold the first season due to the quantity of them.
 * 2) People also likely bought less because SC has already been adapted so many times.

The fact of the matter is that the PV for the initial Part 4 announcement has already out-viewed any P3 PV on youtube by a mile. That already indicates that this is what people are excited for and will likely purchase more of. Even if it doesn't, as long as each bd gets around or over 10k, then who cares if it sales less.