((a)) A board convened under section 2158, 2159, or 2160 of this title shall consist of at least three officers of the grade of commander or above, all of whom are serving in a grade senior to the grade of any officer considered by the board.
((b)) No individual may be a member of more than one board convened under section 2158, 2159, or 2160 of this title to consider the same officer.