I assume you mean crushing blow% / 100% in the formula above.
Huh? That would mean that crushing blow is useless against magic, rare and epic opponents... That would make it even more useless than in the model calculation I did.
Assuming we have 2.6 as and 4 multi, that is roughly 10 onhit chances per second against one target. (Unless the arrow pierces it and hits it again (Assuming a single target would be pierced by one arrow 5 times, it would have the chance to cause cruahing blow 5 times, am I right?) causing another crushing blow.)
For the sake of demonstration, lets just assume that is true and every arrow pierces the same target 5 times. That would mean you have 50 chances in one second to cause crushing blow. With 60% crushing blow that equals 30 crushing blows per second.
Now to your formula. That would mean that you cause crushing against a normal enemy you would cause crushing blow 1 in 4 attacks.
(1/4)*30=7.5 crushing blows per second, lets say 8 for easier calculation.
Against magic that number is reduced to 2 crushing blows per second (cps)
Against rare only 0.5 cps
Against epic 0.125 cps
That would mean you have to attack an epic enemy for 8 seconds to cause one crushing blow.
Is that right or am I just not getting this formula (I study engineering though >.<). Please explain it more precisely!