Over the recent years, the growing research interest in Product-Service Systems (PSS) design and development methods has generated a large background of theoretical knowledge, conceptual methods and application case studies. After analysing the research gaps emerging for these advances, this paper propose a new integrated PSS design method, which intends to associate to 3 key contributions: an increased degree of integration among all components of the method; a higher applicability in industrial companies; specific added-value in balancing economic models of the stakeholders of the PSS delivery network. The proposition is based on extending the Functional Analysis (FA) approach (NF X 50-100), which is commonly used in product engineering, in order to cover the requirements for PSS design and development. The paper intends to provide a conceptual justification, then an industrial verification, of the pertinence and applicability of the method proposed. The industrial experimentation is developed on an industrial PSS case study dealing with the design of an industrial cleaning solution.