Additional Prerequisite(s): Combat Reflexes
You can make one additional attack of opportunity each round with your off-hand weapon.
I am looking for help understanding this. I'm pretty sure this means that you may exceed your AoO limit (1 + dex bonus from combat reflexes) to do one more AoO if given the opportunity, but it needs to be from an off-hand weapon (half strength damage).
This isn't in anyway saying that when you take an AoO that you can also use your offhand attack in there too? If so, they'd spend an AoO each?
I think it only gives you an extra op attack with your offhand weapon. It says "additional attack of opportunity", if the enemy only provokes once then you only get to use 1 op attack against them, which means that you can use either a regular op attack or this additional one, but not both.
Cool feat though, i'll have to put it in the lineup for my two-weapon warrior.
Also consider combining this with Double-Slice to get full str to attacks on that offhand weapon.