82In respect of the period since the previous distribution of surplus, or in any other respect as the directors may determine, the directors may provide under any policy an interim bonus addition or special bonus addition or terminal bonus addition or other forms of bonus addition on such basis or bases and at such rate or rates as they may determine, and the directors shall have power to amend such basis or bases and rate or rates, or to suspend payment of such interim or special or terminal or other bonus additions, at any time.