As described in previous units, there are several opinions to execute a production planning in SAP S/4HANA with or without PP/DS. To combine both planning philosophies is the challenge of MRP Live.
MRP Live can combine both algorithms, MRP in SAP S/4HANA and advanced planning in PP/DS.
For all materials which are activated for PP/DS using the advanced planning flag in the location product a planning in PP/DS will be executed. For all other products the planning remains in SAP S/4HANA. MRP Live is able to combine both planning algorithm in one planning run.
This means MRP Live execute the PP/DS planning and the production planning in SAP S/4HANA in parallel with one constraint. During the MRP Live planning takes the standard heuristic from the Global Parameters and Defaults in Customizing or the heuristic from the location product into account.
In case you are using a planning run with a setup of various heuristics, this can lead the following situation: first you are planning your demands using different detailed heuristics. After the PP/DS planning run, an MRP Live planning run should be executed to also plan the non-PP/DS based materials/components, based on the results of the PP/DS materials. During this planning run in SAP S/4HANA, MRP Live also re-calculates the PP/DS products and reschedules also their receipt dates and times. This means the following: the results from the detailed planning run are then gone.
This undesirable behavior was also valid in an SAP ERP/ECC and APO/PP-DS scenario. The solution there was to assign to the PP/DS materials the special MRP type X0.
In an SAP S/4HANA PP-DS scenario, this has changed. Here, you have to exclude these products in the definition of the planning scope. You can do this, for example, by using the material number as a selection criterion, or a different MRP Planner assigned to the PP/DS materials.