Well, Kuu herself did talk about SUMMER of LOVE like it was a single and it even sold like it was a single rather than a album so it's possible that those songs will be on a new album. I don't like the idea myself because SoL was a album. On the other hand, however, if the next album has the same music direction as SoL's new tracks, I don't mind.
But usually with Kuu we can't really tell for sure what kind of album will be released next so we just gotta wait.
And yeah, I hope she will release something before those 15th Anniversary special lives in December. It would be awesome if there was a new song in the setlist. I don't care if it's a digital single. I just want something, haha.