We describe an application of a custom-designed model-based decision tool system to analyse the workload balancing problem at an assembly plant of Nokia Telecommunications, a Finnish manufacturer of highly customized electronic products. Our system was designed to control effectively and manage the production process of electronic devices for telecommunications link systems and satellite communications systems, among others. It assisted management in determining accurate workload forecasts, in anticipating bottlenecks in the production process, and in providing recommendations regarding how to distribute the production load optimally over the planning horizon. In particular, the system facilitated a trade-off analysis between important competitive factors, such as system throughput time and labour costs. Interesting side benefits emerged from the study.