Like all +4 weapons, the DM adds +4 to the AC hit when using this weapon but the damage bonus has already been factored into the damage wheel.
This item may not be equipped if the resulting melee To Hit, or melee Damage bonus on the party card would exceed 10.
Q1) If my melee To Hit and Damage bonuses are 10 or less before I equip this weapon but equipping it pushes at least one of those bonuses over the cap,