Business-to-business Product Service System (PSS) solutions are characterized by intensive interaction among PSS providers, suppliers, and customers, as well as an integration of physical and immaterial solution modules. These factors increase the complexity and interdisciplinary of such offerings. Furthermore, the characteristics complicate sustainability assessment and monitoring of PSS, as environmental, social, and economic concerns have to be integrated into a PSS by minimizing negative impacts of the PSS on these three axes throughout the PSS lifecycle. The indicator-based framework "PSS Sustainability Assessment and Monitoring (PSS-SAM)" has been specifically developed to support managers and decision makers in dealing with the complex situation described above. This framework considers the most important sustainability aspects throughout the entire PSS lifecycle and adheres to European standard requirements. The results of a previous work have already confirmed the usability of the framework to assess the sustainability of one PSS module (availability of spindle) within a single PSS lifecycle phase (operating phase). The aim of this paper is to present the improvements of the PSS-SAM framework that facilitate sustainability assessment of PSS solutions with multiple modules throughout their entire lifecycle. The improved framework has been validated by a case study of an industrial micro-production PSS solution including multiple modules (spindle, maintenance, training, etc.). The long-term goal is to develop IT solutions that support the sustainability assessment of PSS.