Be careful when you read that, avoided hits (in our case Dodge/Miss) extend our current value of Vengeance, it doesn't increase it. Therefore, if you jump into a pull, pop SD, and dodge the first couple of attacks, you extend your current Vengeance... if you started at zero Vengeance, you'll be at zero after avoiding those attacks. You need that one initial hit to give your Vengeance a large boost, then avoiding attacks is less detrimental to your threat.