About Perfect Agony node on dot skills

Yes GoldDragon is correct (Check previous post, it was a good one). Poison only cares about your BASE DAMAGE potential, not the actual modifiers that become ACTUAL HIT damage. That means you could put Chain on your poison projectiles and they would still apply full poison damage despite the -45% damage to hits that chain is going to give you. So you can put Volley. Greater Multiple Projeciles and Chain together, and totally light up a group of mobs with poison dot, if I understand correctly, despite the fact that your actual hits would be doing almost no damage.

Which when I think about, kind of makes sense, if your plan was to actually poison your enemeis, why use big arrow heads, just shoot darts at them made out of plastic or something.