You guys are too easily impressed!
The hole in the tip is connected to a venturi and so the fuel running through the dispenser creates a vacuum. It's like a carburetor in reverse - sucking in a teeny amount of air into the liquid fuel. Air is easy to draw in, but when the liquid level reaches this hole, and liquid is harder to **** in than air, a trip mechanism shuts the fuel flow off.
Early or late shut-off means that liquid is hitting the nozzle tip sooner or later than expected. It might be the curvature of the filler tube leading to the tank, where the vent from the tank merges with the filler tube, the length of the filler tube, diameter of tube, etc, etc...
Don't forget that the car companies would rather the nozzle shut off sooner. They fought like cats and dogs with the gasoline marketers about who would be responsible to capture the fuel vapor that is pushed out of the tank as the liquid level rises. (Gasoline marketers lost that battle and had to install the rubber accordian on the nozzle to coverthe fill hole.) Having gasoline spray over the fender kind of defeats the purpose! I wonder if someone with a car still under warranty can get the dealership to adjust something, since it is an "emissions" issue. Just a thought.