That's comic sales as a whole... ? You forget to mention that it was also the #2 book of that month, following behind Batman.
Comic sales are in a bit of a slump, yes. However, if books that do their own thing, like Batman or Superior Spider-man are beating (or coming close to) your line wide crossover in sales, why not focus on doing more in-title "events" like those books are doing? Marvel is perhaps even more guilty of this, but if events are not selling significantly better than standalones, why insist on ruining the narrative consistency of half your line for 6 months of the year? I don't even see much of a boost for the tie-ins like we got back in the mid-late 2000s.