200k self heal over the course of one fight assuming 6 healers is nothing. That's about one big healing cast each. That's one big heal you didn't stop in time. No big deal.
...but for 10 man raiding with 2-3 healers this might be a different story.
IV is situational. I will pur it into my second prot spec and try to exploit the living daylights out of it. If sucha thing is possible.