The diagram loads are at best a SWAG (scientific wild ass guess), but are useful in determining if the machine still works the same as it did last time. To achieve good repeatability, it needs regular calibration.
My own recommendation to myself is, if I need the results because nothing else is available, just divide everything I got from that machine by ten, and that's the maximum design load, including all safety factors. Easy to do, easy to remember.
Contributors to this page: Thomas Yost (TDY), Patrick Poirier (PPR), Gerald Maroske (GUM) and Hendrik Maroske (HHM)