[2.2] Phys Crit Iron Commander Siege Ballista || Atziri Down || Budget

increases that affect the poison gem: 100% (drillneck) + 41% (projectile damage increases on tree) + 60% (proj increases in ascendancy - i get Fast and Deadly) + 20% (chaos damage from Fangs of the Viper on the tree) + 12% ( attack damage increase from Coldhearted Calculation on the tree) + 20% (ish) (from the pooison gem itself) = 253%

MOREs that affect the poison gem: (lets say our gems are not highest level) 26% (slower proj) * 26% (pierce) * 40% (projectile weakness curse)

After all the calculations i get 78.4%. So in my setup the poison gem gives me 78% of my attack damage as dot on the target instead the usual 10% a poison not from the gem would. Per sec. For 2 sec so its 156% attack damage over 2 sek - it is like a double damage for every attack i deal (for the sake of clarity i did not calculated Hatred aura or Herald of Ash elemental damage)
And that is not considering other stuff like Far Shot and Point Blank - they also double dip.

Edit: forgot to consider the Rain of Splinters penalty and the MOREs from the frenzy charges; also since i started using Poison gem i removed Point Blank and i definitely do not regret that. Charge generator and curse setup i am using is a 5link in the bow with this gems:

Frenzy + GMP + Power Charge on Crit + Curse on Hit + Projectile Weakness.

Why not Faster Attacks gem?

I think with the totem and ppad penalty the quantity of attack speed i need to get from 1 gem to outperform other gems would be far above what the AS gem gives. I am not saying attack speed is useless but i think once i have so many damage increases on the tree that i get more benefit from 1 point in attack speed than from 1 point in damage increase then i would just focus on some AS. At the moment i have already 59% attack speed increase from the tree and ascendancy without aiming for it at all and that also reduces the benefit from Faster Attacks gem compared to something with MORE multiplier.
I am thinking like this: I place faster all 5 totems = i shoot 5 times instead once so in a way totem placement speed outperforms attack speed when considering clear speed on maps.

That is only what i think and i guess the FA gem would feel like quality of life improvement with totems shooting once every second, but i am happy without it.

Sorry about the wall of text; i hope someone will take some idea from what i typed and improve his build or would give me some feedback so i can improve too :)