For those that calculate your expected uplift beforehand as a matter of airmanship, what would you do if the uplift was 1000 litres less than what you expected? Delay departure and investigate, or go anyway?
Obviously, you'd check it out. Either the tanker gauges are wrong or the aircraft FQIS has developed a fault. Tanker? You could be paying big dollars when you didn't get the fuel. FQIS? Good thing you picked that up; do a dip to verify actual FOB.