There are far too many variables to be able to quantify it as simply a difference in weight. Yes, in raw physics, E=MC2, but "carry" cannot be predicated on that factor alone.
All other factors being equal, a 16lb ball at 16mph creates more raw force than a 15lb ball at the same speed, but then you have to account for all the variables and how those interactions affect the balls interactions with the pins.
A lighter ball WILL carry better for some, but not for all. I've seen people who actually carried better with a 14lb ball than either a 15 OR a 16, but that is because it was more perfectly matched to their style than any other weights.
Those stinking, intricate variables. They'll screw up a great equation every time.