They may skip a year then do the anime as another option too if they know for sure it’s gonna end by a certain pointRumor is that next season will be the last which I could see being the case considering that they adapted 7 volumes this season and they'll be 4 volumes away from where the Manga currently is after this season's finale. If Hori decides to drag it out some more then I bet, it'll end on a movie, but the anime is catching up fast since Hori has been taking breaks.