NO. I think S16 is reasonable though.
Your Defense is pretty good. Your Rebounding would be, presumably, better in the man D and it's pretty good right now in the Zone. Your Stamina is very good and I don't see you suffering any drop-off in man defense. (except maybe in long run and gun fights at fast tempo against good teams, maybe a little then, but not much).
The main thing I see is lack of offensive depth. And, secondarily, but related to that, I see a semi 1 dimensional team. You shoot 3's but not at an very efficient rate. Your most prolific 3 point shooter shoots roughly just under a third of his shots from 3, but makes just a bit over a third of those. not bad, but also not scary either. Very GOOD, in fact, for a PF, but also NOT what you are looking for in a guard position. If you played him as a PF or C, he would be an awesome weapon for spreading the floor on your opponents, but in doing so, you would be exposed in your biggest weakness...... an almost non existent backcourt 3 point threat.
The first time you see a team equal in talent, but superior in perimeter play who has the ability to EFFECTIVELY sag in on you, you'd likely be headed home. You have a very nice team and also a very good team. But one dimensional championship teams win because they are simply overwhelming in that single dimension, and that your team is not.
Switching to man2man will not hurt you with a team like you have, but running into an offensive juggernaut with comparable defensive skills will.
Edited for spelling and correct terminology. :)