Was just curious if the bleeds from the pierce styles stack with each Other?

They do not for celtic dual so I dont assume they do for pierce... at least for one person... if bleed styles generally stack for different persons i cannot say but i have not observed the opposite... several bms sidechaining in bog melee and i never observed a message that the mob already bleeds or observed the bleeding stop prematurely (as it happens for normal mentalist dots when sb else casts the same dot on a mob)

Highest bleed overwrites and if you reapply the same level bleed it'll just start the counter again.

You can't apply a lower level bleed if a target already has a higher level one.

That's the way it used to work and that's the way it seems to work now.