First, these autocannons even with theoretical ability to attack helos and slow-flying aircraft, are pretty much never going to use this mode of action. Which helo or slow-mover in their right mind would willing fly to within a few km of these ships and make themselves vulnerable to attack? If we are talking about an assault helo attack or an aerial bomb drop, Hellfire-type missiles and air-dropped LGBs easily outrange these types of guns. These autocannons are only going to be used against surface targets in all or almost all cases where they are fired in anger. To say they have a "CIWS capability" is to give them an attribute which they pretty much possess almost none of and will have almost no opportunity to use what little capability they have. Against, pretty much all of these guns are going to be useless against missiles, possibly including the weapon you linked in your post.
Second, you have yet to plot a "CIWS capability" vs displacement graph so no one is yet able to judge for themselves whether the 901 falls on or out of this alleged trend line of yours. If you haven't already done so, then all you're going by is your own mental 'feel' about how you personally think the 901 would fall on this theoretical graph.
