From my understanding, Tob, Nex, and normal nightmare (not too sure) are bosses with the unique loot that gets randomly distributed to one member of the kill/raid party (MVP having a higher chance). I know drop boosters have an effect here, but I am unsure as to its exact mechanics due to the drop system.
For instance in a Nex kill with 21 people, let's say a horn rolls at (1/210) chance. In normal cases, everyone has about 1/21 chance of getting the horn with MVP having a slight advantage. If a drop booster is used, which of the following happens:
A) The booster increases the chance of horn to drop to begin with to about 1/183. Then everyone again has about an equal chance of obtaining the drop again. If this is case, would it not just be a waste for more than 1 person to use a booster?
The user of the drop booster has the 15% increased chance over everyone else given a unique rolls. If this is the case, if everyone used a drop booster, do they not just all cancel each other out?
or C) Something completely different
I have asked around in game and have gotten answers similar to "A" or "B". I was looking for staff clarification here. I apologize if I am completely wrong here about something.