You should read the vol 4 if you think it that way, but well I'm pretty sure Teren isn't dumb enough to change the plot from vol 4 in the end of the story.
Ajisai x Renako chemistry is the best in the story, they care and like each other since begin. Unlike Mai who always forced anything to Renako. But too bad the worst girl always the main girl, but hey at least so everyone is happy
I thought Shiho's arc is over, but guess will have some more chap till she get her happy end?
But man, I really hope author-san will give justice to the other ships, especially Hajime and Momoka