i think this has been aired before but i can't remember the details. the problem was with realtracks not midi. the progression and key structure in the previous post about why the seventh was played was explained by the way the guy who recorded the realtracks interpreted the chord change. i'm not exactly sure but it was that in the sequence entered, the player expected a seventh chord not a straight major - somehow the key signature and progression dictated whether a seventh was played or not.

i'll bet it doesn't happen with a midi only style. maybe someone with a better memory can recall the previous post.