Hi PaulC,
You may wish considering a move to SEP 14. It has Advanced Machine Learning capabilities that are not present in SEP 12.1. These SEP 14 detections, like Heur.AdvML.A, Heur.AdvML.B etc, are catching a lot of malware as soon as it is released into the wild, long before there are traditional AV signatures against them. It's won me over as the more effective version against all sorts of new malware.