Why so much variation from CG to pin?

[NewToBowling]

Being a newly I just recently found out that balls have varying distances from pin to CG. It even comes labeled on the box. Some at 2-3 inches, others even longer.

When manufacturing the ball why isn't there a standardized way to manufacture the balls so they all have the same measurements (I'm talking about the same ball model, Unhinged for example)

Why vary the pin distance? Is it by design because bowlers have different needs and some prefer long vs short or is it simply because how the balls are manufactured there is no exact way to ensure that pin to CG distance is constant?

I'm guessing this had something to do with the various top weights.

[bowl1820]

Heres a whole article that explains it:

MANUFACTURING PROCESS VARIATION:
THE SMALLEST of SHIFTS CAN ALTER PIN DISTANCE and TOP WEIGHT
http://www.itbca.bowlingknowledge.info/index.php/fall-2012/78-manufacturing-process-variation-the-smallest-of-shifts-can-alter-pin-distance-and-top-weight

Basically all the parts used to make a ball have tiny variations in them (densities ,size etc.) and each step in making it has slight variations/errors in them. They all add up and they cause the cg (which the center of gravity is not the actual geometric center of the ball) to move some and you wind up with different pin to cg measurements.

from the article:
"Hopefully this in depth look at the manufacturing process helps to explain the final product results. In theory and in design each ball would be manufactured to have the ideal pin distance and top weight but process variation prevents this from occurring 100% of the time. Although shifts in pin distance and top weight should be expected, the end result provides a greater number of options to drill the bowling ball based upon what the pro-shop operator is seeking to accomplish with the customer."

[NewToBowling]

Interesting read. Thanks