Another improvement comes when the same material is used for different products. Then
we combine the demands from all products to give the overall gross requirement. Similarly,
when several materials are ordered from the same supplier, it obviously makes sense to add
them all to a single order. Now the batching rules have to extend to cover different products,
and different materials from the same source.
A more significant extension to MRP adds feedback for planning. MRP uses the master
schedule to generate orders for materials, and this schedule usually has some variation. But we
saw in Chapter 2, that this variation can be magnified in the supply chain to give widely