Volley does not consume Misdirect charges.
I'll let the awesomeness of that statement sink in for a while.
What does this mean? You can stack some added threat onto the tank/pet/your irritating friend. This would probably be best used as a secondary Misdirect, after the boss is already stationed in the tanking spot.
Parting words: Real Hunters Volley-Misdirect pull. ^^