I have an extremely vague memory that back in the old days a check flight involved loading the aircraft to something like 75 or 80 % of gross. I know we used to load sand bags to do just that, but the practice was not continued for what ever reason.
Have once again extremely vague recollection that CASA required loading to some % of gross. Getting somewhat aged so failures of memory are excusable.
Talking to recent twin pilots, all they know is how the aircraft performs when empty on a check flight.
False training?