*** The Pin to PAP Distance
The flare potential of an undrilled ball is dominated by the total differential of the designed ball (see those published numbers are actually used for something). If the core is so dominant, does the coverstock have any impact on the flare potential? Well yes, but only a small effect and it's based upon the friction it encounters as it travels down the lane. Oil and lane types do play a part in how much fiction can be encountered. So beware that one drilling may match well to one house/center and not well in another! This latter is especially important if you're drilling a ball for another facility. Hence, the pin to PAP distance is used to control the amount of flare of the drilled ball and determines what percentage of the ball's flare potential the drilled ball will have.