Gunslinger Build (Lv. 10-200)

I have two questions about Homing. If advanced homing makes you do 20% more damage, what does regular homing do? It only says the damage the skill itself does, so does it not increase your damage on that monster? It just makes you focus your attacks on it, right?

And also, lets say you focus your attacks on a monster such as... Zakum. Zakum then summons a little Puco to annoy you. Can you still shoot at Zakum even if Puco is in your melee range? If so, that'd make it incredibly easy for Gunslingers to solo Zakum.