I see folks here are now getting concerned about relatively insignificant density differences in the fuel. Put it in perspective, chaps!
I hope that didn't stem from anything I said. Density differences are invisible compared with other factors such as variations in the aircraft/engines, style of flying, payload on that day (a decent brunch would amount to much more than density differences). I think this has come from a thread digression about the history of billing/uplifting fuel in volume or mass.