MD04 has many hidden powerful and useful functions. Knowing them could make our daily work easier to evalute MRP results.
Set a manual firming date.
You can set a manual firming date by menu 'Edit' > 'Set Firming Date'.
Receipts lying before the firming date are firmed (an asterisk is added to the MRP element)and won't be changed by MRP running. For example, if you increase the PIR quantity to 10 and run MRP again, the firmed proposal (schedule line in this case) within 12.12.2014 is not changed. A new proposal is created to cover the requirement on the manual firming date.
Please note this is an examplle when using MRP type "PD" with blank firming type. Read the F1 help of this field for restrictions and dependencies.