By-product costs are calculated separately from the base process cost roll‑up. You can enter by-product costs manually or have the system calculate them from regular product structures or formulas.

Since by-product costs are to be deducted from base process gross cost on an element-by-element basis, there must be sufficient cost in each cost element of the base process to cover the amounts established in corresponding cost elements of the by-product.

If by-product costs are to be entered manually, use Item Master Maintenance (1.4.1), Item Cost Maintenance (1.4.9), or Item-Site Cost Maintenance (1.4.18). Enter costs for by-products of a base process using the same cost elements as the base process item.