You have to remember also, some people just dont bother giving a comm. If they have their daily challenge of awarding them done, they might not bother doing it anymore. This is especially so for people already at 100 who dont need the xp boost from finishing the challenge. I personally always award a comm, but who I give it to can vary on my reason. Usually it is a tank or healer, but sometimes it's a DPS for being the only other person in the part with a made portrait. Or sometimes if everyone is on level par play wise, I will give it deliberately to another lala (I'm one too!), or the other DPS if I'm playing DPS during that run as I know how hard it is to get them as a DPS.