A Business-to-Business (B-to-B) software development company develops services to satisfy their customers' requirements. Developers should prioritize customer satisfaction because customers greatly influence on agile software development. However, it is possible that a B-to-B software development company has following issues: 1) failure to understand actual users because the requirements are not often derived from actual users and 2) failure to satisfy the future customers' requirements when only satisfying current customers. Although many previous works proposed methods to elicit the requirements based on actual quantitative data, these works had not considered customers and end-users simultaneously. Herein we proposed Retrospective based on Data-Driven Persona Significance (ReD2PS) to help developers to plan future releases. ReD2PS includes Persona Significance Index (PerSiI) to reflect the correspondence between target users, which developers assume based on requirements in releases, and end-users' personas. A case study involving a Japanese cloud application shows that PerSiI reflects the relationship between target users and end-users to discuss about the validity and effectiveness of ReD2PS.