Yet, despite wide spread recognition of the importance of Performance Measurement Systems (PMSs), there are some issues that require further investigations if PMSs are to be effective in their role of support to control. This article seeks to illustrate that the Choquet integral aggregation operators can address the problem of taking interactions between performance criteria into account. But the use of this quite complex approach requires to explicitly define pieces of information aimed at aiding decision-maker by a better understanding of the contribution of the elementary performances into the global one, and at a better assessing of the different ways of improving the global performance. In this view, indexes of efficacy and efficiency of the elementary performances aggregated by a 2-additive Choquet integral are proposed and applied to a case submitted by a SME company.