The thing I find fascinating about these lists are when a title double ships (like Amazing Spider-Man) the second title is always a little lower which means that there are comics shops ordering 10 issues of #655 and 9 issues of #656. That just seems weird to me.
Maybe it means there are a few store owners who didn't notice it was double shipping and didn't order the second issue at all.
Not really. It's just that ALMOST EVERY issue of ALMOST EVERY comics sells less than the previous issue (barring marketing gimmicks, crossovers, variant covers, etc.). I've myself been fascinated by this seeming conundrum.
Maybe some of the bigger retailers just have automated ordering programs that automatically cut orders by 5% every issue