I can't remember them having more CMs than usual, actually my impression is that they had less compared to Kokuhaku no Funsui Hiroba, looks like I've missed something.
I somewhat doubt that there is much connection between a broken 25k mark of another group and Berryz sales, but you never know.
Actually I was avoiding mentioning C-ute in my previous posting, but since their sales are posted here now I would like to mention that this isn't only Berryz best first week sale, that it outsells Mikan's but also is - so far - better than c-ute's first week sales, oh, and don't forget about first day sales. Damn, looks like there are new marks that need to be broken. This way we gonna have 100k sales again soon
But to be serious, the most surprising thing is imho that Mikan sold bad compared to everything, but that has not much to do with Berryz nor c-ute.