the songs that have his name are the songs where he has contributed a lot (70%?). in those songs, the melody is completely his and half of the orchestration is his (Nightingle's name is listed because he also contributed a lot in orchestrating ARRs melodies). thats the story of the 9 tracks.
for the rest, you can still hear some ARR touch, altho minor, there is still some contribution. however, in the album details, ARR is given prime importance as he is the major contributor (his name is listed first, vartinna, and then nightangle). neways dont worry about who did what. just listen and you can feel ARR where his contributions greatly exceeds others (which are the 9 tracks).
