Architectural aspects are expected to modularize widely-scoped concerns that naturally crosscut the boundaries of system components at the software architecture level. However, there is no empirical knowledge about the positive and negative influences of aspectual decompositions on architecture stability. This paper analyzes the influence exerted by the aspect-oriented composition mechanisms in the stability of crosscutting concerns in an evolving multi-agent software architecture. Our investigation encompassed a comparative analysis of aspectual and non-aspectual decompositions based on different architectural styles. In particular, we assessed various facets of components' and compositions' stability through such alternative designs of the same multi-agent system using conventional quantitative indicators. The evaluation focused upon a number of architecturally-relevant changes that are typically performed through real-life maintenance tasks.