Here is how I imagine item drop works. You're killing dm with your party. You kill 1 every 30 seconds and after 10 dm you got one raptor. there is another party next to you but they kill slowly. they kill one dm per minute. After 10 minutes they got 2 raptors. Why? because you got the ones without drop.
P.S. I don't know koding, I don't know anything about how game works database wise in these subjects but as a player that's how I imagine it works. It's all about luck.