If you have created a new MRP-relevant material that supports both in-house production and external procurement, you need to specify the procurement type for the material in the material master record. The procurement type determines how the material is procured, either in-house, externally, or both. If you do not specify the procurement type, the MRP run does not consider the material, and it has to be planned interactively using the MRP Live app or the MD04 transaction. In interactive planning, you can manually assign a procurement type to the material and create the corresponding order proposals, such as planned orders or purchase requisitions. Alternatively, you can maintain a production version for the material, which defines the procurement type and the BOM and routing to be used for in-house production or external procurement. The production version can be assigned to the material in the material master record or in the MRP Live app or the MD04 transaction. The production version allows the MRP run to plan the material automatically based on the specified procurement type123. Reference: Procurement Type | SAP Help Portal, Production Version | SAP Help Portal, Material Requirements Planning with SAP S/4HANA, page 79-80.

A multiple bill of material (BOM) is a type of BOM that allows for different combinations of components or raw materials for the same assembly or subassembly. The reason for different combinations of components in a multiple BOM could be the manufacturing date or the lot size. The manufacturing date determines the validity period of the BOM, which means that different BOMs can be valid for different time intervals. For example, a BOM can be changed due to a design modification or a change in the availability of components. The lot size determines the quantity-dependent explosion of the BOM, which means that different BOMs can be used for different production quantities. For example, a BOM can be optimized for different batch sizes or different production methods. Reference: Multiple BOM, BOM Explosion

Materials that have a negative quantity in a bill of material or in a recipe are those that are produced in addition to the main product during a production process. They are either sold or disposed of, and their costs are apportioned among the main product and the co-products. By-products are materials that have a low value compared to the main product and are usually not planned in advance. Co-products are materials that have a high value compared to the main product and are usually planned in advance. Waste products are materials that have no value and are discarded or recycled. Reference: Bill of Material (BOM), Test sap pp 2020 s4 hana - DAYPO

The planning strategy Finite Scheduling with Reverse allows you to schedule production orders backwards from the requested delivery date, taking into account the available capacity and material constraints. To allow scheduling the past, you need to specify a negative offset time in the strategy profile. The offset time defines how far in the past the system can schedule the production order start date. For example, if you specify an offset time of -5 days, the system can schedule the production order start date up to 5 days before the current date. This can help you to avoid late deliveries and reduce lead times.