The certification container is 5 gallons and the fill must be within ml’s in order to pass and become/state operational.I just looked back at this thread and saw the thing about getting more gas when it is cool.
Fuel, in most cases (except maybe airports and military bases), is stored in underground storage tanks and usually below frost lines in cold climates.
The temperature of fuel pumped would remain pretty constant, no matter the time of day or night and no matter how hot or cold it got.
In the US, fuel pumps selling to the public have to be measured and certified by the local/county Inspector of Weights and Measures for accuracy. If the pump meter shows 1 gallon, the inspector's test container has to be filled to 1 gallon.
This is not because they care about us, really. It is about making sure the local/state/federal gas taxes are charged accurately and pumps have not been messed with.
I don't believe the claim made by the "How Stuff Works" blog...