Many bowlers motivated to knock stuff down, use the heaviest ball they can handle. As I have mentioned before on this forum, if grip pressure is minimized, the ball lets go of you. If the ball doesn't pull you around, there may be something else keeping you down.
If your game is built around solid execution of spare shots, improving your first ball carry and strike percentage will raise your average. Less pins to knock down or NO pins to knock down make the second shot easier. The weight of the ball may cause you to have slower ball speed, requiring a ball, layout, and surface prep to compliment your game.
Your speed and rev rate helps create the path to the pocket. Matching the two provides the effect you desire at the pins. If the ball hits weakly, or rolls out before hitting the pins, you may need to address where you play on the lane, whether you need a smoother/shinier surface or even an easier ball to get down the lane (higher RG - Radius of Gyration, or higher RG drilling).
Weight is one element of your ball that helps knock down the full rack of pins. If the ball fits, your swing is easy and free, and the ball provides the skid, hook and roll needed for a good angle to the pocket and continuation through the pins, you will improve. If better form would help, seek out a USBC or IBPSIA Coach in your area. Check their websites: bowl.com or ibpsia.com.