An Alerts stat would make sense if it was broken down into categories - there are different degrees of ghosting success, e.g. regular ghost allows first level alerts ("thought I heard something"), while stricter modes do not. Also, an objective measure would be better than one that's based on some arbitrary form of weighting. Just my opinion, of course, and certainly not game-breaking if it is done otherwise. After all, TDP/TMA had no score like this.