Curious about the physics involved in changing weight? (This may get me a negative 'hit' on my rating, but what-the-heck.)
Basiclly speaking, the ball in motion is using Kenetic Energey (K.E.) followed by the Potential Energy used to move the pins. If we increase the K.E. we increase our 'hitting power'.
K.E. equals 1/2 mass (we'll use the ball weight) times the velocity squared (we'll use MPH).
(My apoligies to any physics majors reading this):
Let's say you throw a 16 pound ball 60 feet down the lane in 2.15 seconds. That's about 19 MPH.
The Kinetic Energy would be 1/2x16x19x19 or a K.E. of 2888. <-Remember this number.
Let's lower our ball weight by 6% to 15 LBs:
1/2x15x19x19 = 2707
and again by 13% to 15 LBs:
1/2x14x19x19 = 2527
Looks like you shouldn't reduce ball weight? Look again:
If you throw that lighter ball (15 LB) 1.5 MPH faster (approximately 1/10th of a second faster):
1/2x15x20.5x20.5 = 3,152! (remeber the hitting power for the 16LB ball at 19MPH?)
Understanding that more Kinetic Energy results in more potential energy released on the pins...
Well the decision is yours.
Keep in mind that you would need to throw the ball CONSISTENTLY faster. (The WORK you generate to deliver the ball would need to be the same as the WORK to deliver the 16 LB ball.)
And we didn't even get into rotational Kinetic Energy....