Quote Originally Posted by Zfz View Post
Total damage taken over the course of the fight only ever matters when your healers are going OOM during the fight. Any other time, what matters is the damage taken between heals, and there are two things tanks can do about that: use a cool-down, or have more effective HP.
I think you're a little confused by the actual meaning of this term considering mitigation comes into play to determine eHP. It has absolutely nothing to do with hitting the max available HP at any given time. Plenty of old discussions on this topic, use the search function if you'd like to go read them and brush up.