Before i answer this understand I'm probably wrong. This is just how i understand it.
When you look at your Acc rating tool-tip it has Acc rating broken down for 2 different attacks. Basic and Special attacks - I understood as that I need 108% Acc for special attacks which would govern any ability that uses rage to deal damage including ravage, and that basic attacks cover Assault and Battering Assault.
So keeping your Acc rating at 100% on basic attacks you would have 110% Acc rating for special attacks - 2% to much. I run at 98% Acc for basic attacks keeping me at 108% for specials. I've never seen any special attack miss. I have seen Assault and Battering Assault miss on occasion not being at 100% for basic attacks but they do build the same amount of rage regardless and the damage from those 2 abilities make up less then 2% of your overall damage. So I can live with not having 100% Acc rating.
So yes, as I said I'm not doubt wrong. It's just my take on it since the number crunching hasn't been officially done yet - Food for thought.