I agree with all up above. Oil volume determines focus point.
Heavier = closer dryer = farther.
Quick example, one day went in with my medium condition ball only.
Couldn't strike at all(looking at arrows). Started to pack up. My pro friend said why are you leaving?
I replied, "It's real wet, I've got the wrong ball and I can't strike!". Heading home I'll practice another day.
He said, "Loser!", there is a way to strike and I'll prove it too you.").
He got me aiming at the close dots and even a little closer. After about two balls, voila! 17 in a row!
REgards,
Luckylefty
PS it is fun to learn.