Oh, I guess Grenolith was using concusive shot to get the extra damage out of stead shot. I could be wrong, but this uses more mana than steady shot and also uses a global cooldown and I'm thinking that steady shot give more bang for you buck?
Oh yeah, as I understand it, Explosive Shot is supposed to have priority Black Arrow. Shouldn't Black Arrow be used before ES on the pull? I haven't tried in an instance yet, but when I open with SS-->ES-->BA that i'm way more likely to pull aggro than I am opening with SS-->BA-->ES.