By-products that require no additional processing after the point of separation are often accounted for by assigning

Question:

By-products that require no additional processing after the point of separation are often accounted for by assigning to them a cost of zero at the point of separation and crediting the cost of production of the main product as sales are made.
(a) Justify this method of treating by-products.
(b) Discuss the possible shortcomings of the treatment.