SEOMike - 2:16 am on Jul 7, 2005 (gmt 0) Just a guess here... let me know if I'm wrong. :)
Ever hear all the bubbling just after the pump clicks off? I'll bet it's those bubbles that rise to the top of the fuel filler tube that cause the vacuum to change thereby shutting off the gas. That'd probably give at least 6 or so inches of fuel level (in the tube) before gas actually hit the tip.
Just a guess here... let me know if I'm wrong. :)