Looking for clarification on why MRP is create P’req lines when there is open supply lines greater than the safety stock.

The Safety Stock on this item is 6, the Minimum Lot size is 12. There is 0 on hand and 20 on a purchase requisition (seen above). The P’req was entered manually and as a result of a previous MRP scheduled task.
Should MRP consider all open po’s and requisitions when calculation MRP amounts?
