We often used "all adult weights" or "standard charter weights " which came close to 76KG an adult, probably so the baggage could be "legally loaded"! Looking at some of the Arab country and German pax, 70KG for a female was about half right and the male weight was ludicrously low. On 280 pax we could have early been 3000 KGs out, but as long as we showed an underload no one gave a hoot. The thrust difference on this flight was the width of a fag paper.