Sometimes b-sides are just to help fulfill a single and the artist doesn't put that much efforts in the song anyways (Most often b-sides don't even make it to the album at all)...just like a little bonus. However sometimes it's funny because the b-side sometimes is a lot better than the a-side
I've seem such things happening several times (Reminds of Aikawa Nanase's single R-Shitei)
Under the moon freaks me though
I could never tell whether that is an a-side or b-side...i mean, it is an awesome song, it pairs with Under the sun (even though the name of the single is just Under the sun), It has a PV, the PVs of both songs matches ("Which do you like?")....Why the heck wasn't it featured on TRUE SONG though? That album still had a lot od space....One or Eight made it but Under the moon didn't...go figure.....