The identification of process alternatives with reduced product cost is one of the major tasks of process development and optimization. The article covers central aspects of flow based analysis methods. Material and energy flow analysis is extended by cost flow analysis and applied to chemical process development. Using an example from process development, it is shown that the method of cost allocation to flows leaving production steps influences the recognizability of cost reduction options. A more thorough analysis for better understanding and deduction of recommendations for practical use would be beneficial.