Patch 4.0.6 (8-Feb-2011): Balance of Power’s tooltip now states that spell hit rating is increased only by Spirit gained from items and effects.
Patch 3.2.2 (2009-09-22): Misleading tooltip reworded. The tooltip previously reported an incorrect value for the increased chance to hit with spells. The actual benefit of the talent is unchanged.
Patch 3.2.0 (04-Aug-2009): Now reduces all spell damage taken by 3/6%, rather than reducing the chance to be hit by spells by 2/4%.