How it would work? 1) User adds base product with net wt and gross wt. 2) When user adds multiple products in a carton (for e.g.) the net wt and gross wt of total carton is calculated. Why it is needed? Because exports are charged on the basis of weight and a lot of time gets spent to calculate weight for each shipment. What does it need? It needs multi unit feature to be already present in the software.