I just want to share this, I have been doing it for a while now.
It started when I was getting vps with my archer in AC.
my archer was killing the whole time, got about a few mets a few +1's (just the normale things you always get) then there was 1 mob left. killed it with my trojan. what did it drop: super attack ring.
Dont think that was my own pure luck. but just a part how this game is made.
After a while I had a friend who came to AC
I was killing everything. I ask him to kill everything 1 time. he did. mobs spawn back. I scattered and got 2 mets.
Seems like if you are @ a spawn. the drop rates will go down after a while.
ask someone to kill some things 2, and then you can continou hunting.
You can say its bull, and it might not work..but keep trying. for me it worked alot.