Service-Oriented Architecture (SOA), which supports various features such as the interoperability and reusability of IT resources, comes into the spotlight as an effective approach for adapting new business environmental changes. SOA, however, has some problems including the high realization complexity and low Return on Investment (ROI). As a solution for these problems, Web-Oriented Architecture (WOA) has been gained attentions and expected the flexibility and reduction of complexity to be indeed achieved with simple implementations using RESTful services and mashups. However, it also has some drawbacks related to security concerns and unstable message transmissions. In this paper, we propose a novel integrated model that combines the advantages of both SOA and WOA seamlessly. According to the characteristics of a service, the proposed model applies SOA or WOA approach selectively to provide an appropriate way to implement the service. We employ the proposed model to design an actual financial software suite and validate its effectiveness using the well-known function point analysis. Estimation results have shown that our model can reduce the function point of the financial software up to 38%, compared with the legacy SOA based software, while satisfying diverse customer's requirements.