Lead at 3/9 o'c will also improve twist weight (torsional stability) as well as improved power. It will also add power to the side areas of the stringbed if you hit off center.
You can also add lead at noon or above the mid-point of the head to move the sweet spot higher. This helps with serves which a lot of people hit higher in the string bed. And, some people hit their groundstrokes higher.
So, you can do different things with lead and tension.