Hyper_Dispatch.
There should be NO Difference in the Weights (providing correct/latest basic data used).
But there will be differences in the Trim.
Using Manual Trim Charts or (god awful) Whizz Wheels, builds in small errors. Some of these errors cancel themselves out, some are cumulative. Because of the design of the Trim Charts, the result is still safe, but from comparision testing Computerised Weight and Balance Systems against production manual loadsheet/trim charts (a long while ago), the differences can appear large!
I believe all staff who's job involves Loadsheet/ Load Planning functions, should receive training in Weight Balance basics and then production of all manual Load Plans and Loadsheet and Trim Charts.
I also believe that Whizz Wheel Trim Calculators should be banned (but I accept that isn't going to happen any time soon).
DIH