Over the last decade, several authors have studied the maintainability of software architectures. In particular, the assessment of maintainability has received attention. However, even when one has a quantitative assessment of the maintainability of a software architecture, one still does not have any indication of the optimality of the software architecture with respect to this quality attribute. Typically, the software architect is supposed to judge the assessment result based on his or her personal experience. In this paper, we propose a technique for analysing the optimal maintainability of a software architecture based on a specified scenario profile. This technique allows software architects to analyse the maintainability of their software architecture with respect to the optimal maintainability. The technique is illustrated and evaluated using industrial cases.