This paper addresses the dilemma of designing and operating production systems with high resource efficiency and at the same time high flow efficiency in an environment with low volume mixed model production and large variations in the supply chain. The consequences of performing Value Stream Mapping (VSM), and using Lean, in such a variable environment have been analysed in this paper. The analysis is based on about ten years of experiences from conducting VSMs and performing production planning in this particular environment. One of the key issues is how to create a system that is flexible enough to manage variations and changes.