Performance measures play a critical role in formulating mail delivery strategies and evaluating actual results. Nevertheless, the existing method and corresponding system to determine the standard workloads of mailmen is developed without careful consideration of real delivery environments and various requirements of mailmen. Hence, the current system is insufficient for optimal management of workloads and shows substantial gaps when compared to the results of actual work-site. This study considers how to improve the current workload management system of mailmen. We first performed the as-is analysis of the mail delivery service and then developed a prototype of advanced delivery workload management system. The to-be system consists of five subsystems which can be grouped into three categories; master data management, workloads management, performance analysis. Our results can be a valuable guide for the development of real system for measuring and balancing the workloads of mailmen.