In supply chain management literature multi-item multi-echelon systems are the vehicle to study concepts like bullwhip, Vendor Managed Inventory (VMI) and postponement (cf. De Kok and Graves (2003)). Whereas the bullwhip effect is typically explained from studying serial multi-echelon systems, VMI and postponement are typically explained from studying multi-echelon divergent systems. Both VMI and postponement benefit from the so-called pooling effect: downstream variability is pooled such that the joined variability is relatively lower and thereby inventory capital investments can be reduced while ensuring the same customer service as before pooling. With VMI pooling is achieved by transferring control (and sometimes ownership, too) of items at customer locations to the supplier of these items, thereby moving from decentralized control to centralized control. With postponement pooling is achieved by redesigning products and processes, so that diversity is moved further downstream, so that pooling is achieved over a larger portion of the cumulative lead time in the supply chain.