If that rate of usage was ever true, you would be smelling gas.
I have had two gas leaks from cracked hoses (Supply and return) under the EGR valve at 44k mi.I have also had the jumping gas meter condition so popular with the VX. There was a time in 2003-2004 when the oil refiners left alot of sulfur in the gas which formed H2SO4 and ate a little of the sender wires. This made the national news. I do not think anyone got a refund. This was said to be localized in the south, but mine failed at just that time. Since the oil companies are making so little now, we should not be suprised that they cheat a little in processing. Greed knows no bounds (If you have no recourse-of course.).
Roy