Protection: Impending Victory (Victory Rush)

I have searched lightly for this and found no relevant thread so I figured I'd go ahead and post my small amount of math and thinking I've had going behind this.

The premise is pretty much these three things:

Victory Rush

Impending Victory

Glyph of Victory Rush

Field Dressing

From what I understand the math to calculate for how much you would be healed using Victory Rush from a proc would be:

0,05*1,06*1,2*1,5=0,0954

Which means that a Victory Rush proc should heal you for 9% of your maximum health.

Once the boss hits 20% and we assume you're spamming devastate and using Victory Rush every proc avaliable, would it be reasonable to simplify the rotation down to:

Devastate -> Devastate -> Victory Rush

If we go with this it means that simplified you will be healed for 9% of your health every 4,5 second. If we have a tank with 150k hp (an imo realistical number). This would mean that they would have a HPS of:

(150000*0,0954)/4,5=3180

Correct?

This would in turn mean that a warrior tank during the last 20% of a boss would be able to have a stable selfhealing on himself for 3,18k HPS, gimping threat and damage.

I don't know what numbers healers are at these days but would this not be quite viable?