Think of like this see if it helps. You picked spot to hit like when throwing a rock in to a bucket at 30 feet away, your margin of miss is 2 feet around the bucket, you use throwing item that has a forgiveness of plus or minus 1 foot. The margin of miss was 2 feet the item has 1 foot, the margin is now 1 foot.
The ding is dead on / with built in plus or minus of zero.
The item in example / the dots of foregiveness - say they are 3 inches per dot, in theory you can miss the ding by 3 lines of ding plus or minus but still keep your aim point with margin of error 1 foot.
but in game up hill / down hill 1 foot is adding or subtract about 1 yard of roll.
green break and speed of green also affect where the ball will go as to where we aim.
More Precise gives more accurate results.
More Forgiveness gives less effect when you miss the ding.
you give up 1 to get more of the other. lot of forgiveness no precise / lot of precise no forgiveness.
I seem to get good results from 3 dots of precise and 3 dots of forgiveness, i can miss the ding and still keep it inside a 1 foot circle on the green from 10 feet plus. not great but good enough to keep me happy.