Quick Question About the armor

Does The Bullet Proof Helmet and Bullet Proof vest both work if u have them equipped at the same time? Because I brought both of them and I only got 100 ac before I only had the Bullet Proof Helmet and I only got 100 ac now since I brought the bullet proof vest shouldn't it be 200 ac? Instead of 100?

and the vest doesn't seem 2 be working I've re-quipped it and stuff and re-logged and I've had these items for about 2 or 3 days