This paper investigates the performance of a well-known production and inventory control algorithm, termed APIOPBCS. APIOBPCS is a very general representation and has been shown to cover a widerange of material flow control strategies. We investigate the performance of the general APIOPBCS model and highlight a particularly robust set of solutions to APIOPBCS, termed the DE solutions. The DE solutions have desirable properties relating to stability and the robustness to a range of non-linear effects such as yield rates, stochastic lead-times and capacity limits, We make extensive use of z-transforms and simulation to achieve this aim.