Since this thread went up again...
Just want to say, don’t like Saginomiya when he’s trying to extend the goal post for one more volume.
This and Hiyori had the same problem... it’s right before conclusion, then the author throw another problem to overload them and ends up getting another volume.
Well, at least the voice actress and the radio star’s story are just 2 volumes so it doesn’t went far.
But the time travel story (set after Shiki and Akiha are older) got the similar problem.