This album is part of Starchild's Visual Sound Series collection, this one is dedicated to image albums.
So this album is first an image album related to the manga "Hana no Asuka-gumi!, and then it serves as soundtrack to the adaptation in OVA.
This is not the first time with Starchild Records that an image album also serves as an original soundtrack, see
here for example.
I don't know if all the music from this album is used in the OVA. The track 7 is already an image song.
@TheOSTMaster: is there some music on the track 1 or only narration please? JASRAC credits Kimio Nomura as composer but I'm not sure there is music.