Interesting reaserch.
I wonder though, are you doing it just for the sake of figuring out mechanics, or does it have any actual use in the game? Because having such long poison duration vs the problem of leash range (poison stops working if you move too far from a monster). For example running around circles in fauzt, wait 30-40s until stuff dies, and then you are allowed to move to another screen. Surviving that is one thing, and time it takes is antother.
I think realistically, when it comes to farming, we care about poison dps, and if duration is around our aoe cooldown that spreads that poison, it doesn't matter, because we can't leave these enemies behind.
Reminds me of the old days, back when gamma field druid was a thing (poison spell with ridiculously long duration and moderate dps). People were trying to poison entire map with it, and obviously it didn't work very well. It was the build with charm tree (still in the game), so you poisoned enemies, charmed it to render them harmless, and on top of it one commands lowered their poison resistance.