@HungryIm That's what it looks like - vol. 1 also had 20 chapters and it seems that there is no new chapter planned on the raw page, at least from Yuri Ichigo's tweets.
Don't want to be the bearer of bad news but according to Yuri Ichigo's twitter this is probably the end of the series :( It was fun while it lasted, but I hope that at least this couple gets some proper ending in extras.
@Lilliwyt: Maybe I missed something but isn't Koyuki just choosing her school to go after 3rd year while she is still in her 2nd year? So even if she eventually leaves alone in the end (which I doubt), they still have about 1,5 year together on that high school, no?
Well it was something like she "doesn't intend to define it as yuri but reader can interpret it that way" so I would just wait and see. And if it indeed ends up as heavy subtext with open door for reader interpretation instead of clear label, what of it? If she ended up getting them all...