It's well over.
There was a lot of well thought out scenes in this, mostly past where the anime left off but it's apparent the writing was abandoned by now.
Not because the character/s changed or because of yuri, but because there is no thought behind the events and actions the characters partake in.
Volume 13 is still original tomoko, 14 onward is where it descends into character analysis. There's some good, it's not a sudden death. Once they finish exploring the characters you're staring down a corpse, that's Vol. 16 I'd say. I'm a very generous person.