For the people playing all the same class

I play with 4 shaman and I have noticed that every instance i run i always get the same loottables.

I ran razorfen kraul 15 times to prove it and i never once got a different drop.

I have read that loot rolls to determine the loot table are influences by the class makeup/# of people in the grp/and the lvl of the people.

So I am wondering if this is true. I know a lot of people are 100% convinced its completely random but in fact if you were to change ay of the above criteria you in affect focring a random element.

The other end of it is that these lvling instances, the bosses have very few drops. Jsut the same its fun to think about.

I honestly have never gotten different drops on bosses i have done more than once on these shaman.