It has been a long time since I worried about such things, but it seems to me that one CEP is the area into which a given round will fall fifty percent of the time. In other words, it will fall outside that circel fifty percent of the time. However, the vast majority of the rounds will fall within an area equal to three CEP, I think. As I say, I have not worried about this for decades and one of you - perhaps all of you - will have better information.