the problem with BST is you get like 1% hate or something on the mob (1)
like lets call it aggro hate
this kind of hate is good because your pet will get aggro off you the moment it melees the NM once
Trying to build more hate on the NM is VERY bad since the pet will have to melee him more to take the hate off you
Some NMs hit very hard and could potentially kill you. Oh and Dia is 50/50 since your /whm so if it does 0 and doesn't last long your just building hate on the NM
(1) this is pretty much the reason why the Mob turns yellow/white/unclaimed