Based on her twitter, i think Amatsuka Moe still with S1, and she'll release her video at October, she says that it's like a regular trobule that every September she can't release a video, this happen last year too
From her twitter, it looks like she is in a movie "Revenge Porn" which initially I thought was a switch to another studio but later I think maybe it is a mainstream non-AV movie? I can't get to DMM link so maybe somebody else can check it out.
http://blog.livedoor.jp/moe_amatsuka/archives/65099982.html
edit: oh i guess dmm doesn't block non-adult links so yeah it looks like a mainstream release. maybe she was taking time off to do this movie so no monthly releases for a while.