Thread:Vishkugeta/@comment-26046340-20181125184438/@comment-979971-20181126000938

https://www.amazon.co.jp/gp/product/B07F8QXNNR/ref=oh_aui_d_detailpage_o00_?ie=UTF8&psc=1

They don't seem to have a schedule, it's really random. Volumes 11-15 were all released on the same day.