Focus questions

[Bulce]

I've been reading up on the Spell focus info, have a few questions

I curently use a Burning Affliction V augment. If I was to pick up a Poison only aug with say 35%, would it overwrite the BA aug?
For example,
Bane would get 20% from BA V, Wunshi would get 20%, but would Saryn get 20%, or would it use the higher say 35% damage modifer?
Would th BA aug even be used with the other DoT's?

I don't want to pickup a type specific aug if it would adversly affect my other DoT.

Thanks!

[XeroOmega]