If I believed the measurement of volume was in error, and I could prove it, the gas station would be out of business (especially if it happened repeatedly).
Anyway, we must be talking past each other because there's no way that you could be advocating charging someone by volume of consumption without any way of accurately measuring that consumption. Why don't we just get rid of electric meters and let the electric company tell us what to pay.
The answer is that there's a piece of equipment subject to neutral-party certification (AKA regulation) that measures usage. I don't care who owns it. The same thing would be OK for ISP's, if there was a certified meter that they wanted to place on premises. We both know that's not how they want it.