Actual weight at production works. using calibrated works scale at time of production. This is checked by smart operators against theoretical weight s to manage yield losses/ shrinkage.
The weight is certified on the manifests/Bills of Lading/ export documents.
Weights can also be done at offsite certified scale as was suggested by Suresh.
Receiver can weigh in if they have a scale, can have load re weighed, and tare weight of container subtracted, or cann do piece count theoretical weight calculation.
When receiving goods, we always confirmed piece count and theoretical weight to avoid the uncerteinty of weight of packaging materials which we couldn't appropriately estimate.
milo
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People say between two opposed opinions the truth lies in the middle. Not at all! Between them lies the problem, what is unseeable,eternally active life, contemplated in repose. Goethe