This paper refines a previously proposed problem formulation that can be applied to integrated space station system design. The Integrated Space Station Optimization (ISSO) formulation combines both a space habitat and its supporting logistics design into one single optimization problem. In this way, a space-based habitat and its logistics resupply system can be designed concurrently and effective trades can be conducted between them. This work improves the previous work about the ISSO in terms of the definition of scientific return. The previous definition of scientific return assumes that the trades between different attributes (e.g. upmass and crew time) are possible. However, this is not always true because many scientific experiments have optimal ratios of these attributes. This paper proposes a new definition of scientific return to captures this feature and shows how the ISSO can improve the performance from the aspect of imbalance between multiple attributes. Numerical results show the benefits of the proposed problem formulation for both retrospective and forward-looking analysis.