During the 3rd CIRP IPS2 conference an approach toward communicating the value contribution of different PSS design alternatives using colour-coded CAD models was presented. Building on this work, the paper presents and discusses the results of the testing activity undertaken to verify the effectiveness of the colour-coding approach. The paper describes the setting and the findings of a series of PSS Design Experiments involving 8 design teams composed by master students in product development. Through the application of protocol analysis to the recorded design sessions, the paper compares the behavior of the design teams when using colour-coded CAD models, instead of QFD-like numerical tables, for value communication in PSS conceptual design.