I thought it is easier to read the statement - "Natsukashii Umi" is the opening theme of Kurau Phantom Memory - in the beginning of Notes section as compared to labeling track 01 ----- Opening theme. I see other singles/albums (e.g.
http://vgmdb.net/album/19330 and
http://vgmdb.net/album/19679) mostly doing it the former way, but Phonograph edited to look otherwise. Not sure which is the better way? Even if the latter method is preferred, I'd think it is clearer to enter as 01 - Opening theme of Kurau Phantom Memory. This is just my opinion.