It can be very intimidating for a new bowler to go into a Pro Shop
and have the confidence in telling a "professional" how you want your ball drilled, and that you think they aren't doing it right. I have been there, recently. Until I found this forum and then read many articles on www.bowl4fun.com
I am absolutely no professional, and I could in no way measure my own span or anything. However, because of the knowledge of articles on those two sites, and talking and reading through posts here, I have a much more knowledgeable arsenal to assist me in talking to my driller. In fact, they are happy when someone is somewhat knowledgeable.
They are getting paid to drill, and if you tell them how and why you want it drilled a certain way, then they should oblige. If not, find a new driller.
It comes off much better to a driller when someone says, "Hey there. I am looking to get more backend skid\snap from this ball. Currently it gives me more of a weak arc shot. Can we possibly drill it Pin Up somehow and see if we can get more backend without buying a new ball?"
I am sure that most of the balls they drill are for people who don't care (or don't know) that they can drill differently to get the ball to react differently. They just drill the ball to fit their hand and then send them on their way.