Optimized Production Planning However,MRP-based methods have three major drawbacks: The lead time not only needs to be pre-specified but also is assumed to be static over the entire planning horizon; The capacity is assumed to be infinite,which means the derived production planning may not be realized; The production system is made nervous.Little adjustment in MPS changes the due date,requiring the recalculation of MRP 上浒充通大粤Optimized Production Planning However, MRP-based methods have three major drawbacks:  The lead time not only needs to be pre-specified but also is assumed to be static over the entire planning horizon;  The capacity is assumed to be infinite, which means the derived production planning may not be realized;  The production system is made nervous. Little adjustment in MPS changes the due date, requiring the recalculation of MRP