FP Training past level 200.

doesn't mist eruption deal more damage the more DoT effects the enemy is under?

Absolutely. Mist Eruption can utilize up to 5 stacked dots to multiply its damage considerably. At this point, if you're only training with Paralyze + Mist + Eruption, you're severely under-utilizing your F/P. I've not tried future perion yet but I suggest to always stack 5 dots before exploding if you cannot kill a monster in a few hits.