[AlexanderHowl]

I would actually value it as if it was DR, a -20% for all arms or a -40% for one arm. I am not quite sure what the utility would be for such an ability. If it only benefits the arms, you cannot take steps during attacks (or move), so you would basically be a turret after your first action. I guess you could spend your ATR actions on attack and then AOD (Dodge) on your normal action, so it would have some marginal utility, but I am not sure it is that much better than Extra Attack. For example, you could take Extra Attack (Arms Only, -20%; Multistrike, +20%) [25] and that would be 55 CP cheaper than ATR (Arms Only, -20%) [80], meaning that you could purchase Extra Attack 2 and Basic Move 6 instead of ATR.