So, the booklet credits are a bit disputable.
On page 1 it says tracks 1, 3, 4, 6~9, 11, 12, 16~18 are composed and arranged by reiji kitazato (teng), but the last page also states that those tracks are "written and recorded by koji kasamatsu & reiji kitazato (teng)".
Koji Kasamatsu is credited as sound designer and sound architect on this album. Looking at some of his
other involvements (
other), he either takes the role of the sound designer/recorder or/and that of a
remixer, but rarely as a composer. Since it says "recorded & written" it could also mean that Kasamatsu recorded the pieces and Kitazato wrote them.
So, should he stay credited or be removed from the composer field?
EDIT: After taking a look at the audio drama (which uses the bgm) staff credits, it seems that Koji Kasamatsu only worked as sound designer and teng is the composer & arranger.