BOM (Bill of Materials)
A Bill of Materials (BOM) is a list of parts that are needed to create a finished product (a recipe). It consists of several parts. A product may have several alternative bills of materials.
To create a manufacturing order, the BOM must be associated with a routing.
When a BOM is saved, MRPEasy tries to calculate a cost of it by adding costs of all raw materials used in it. If cost of some raw material is unknown (no lots at stock, no vendors), then total cost of BOM cannot be calculated.
If Matrix BOM functionality is enabled and a BOM includes a relation, its' cost also cannot be calculated.