How to deliver the high service quality to customers is one of the most important issues during the past decades. Unfortunately, these service quality discussions are mainly focusing on provider side instead of customer side. What if the proposed service strategy does not fit customer's needs because the customers have different perception of their needs? This may become a considerable gap for provider companies providing service to satisfy their customers. In this regard, the purpose of this study is to explore the gaps of information system service quality inside the customer organization. Our research objects (i.e. customers, customers' supervisors) are those who participates the information system needs assessment process and determine what the system should look like. The result shows that significant difference of the perception of service quality between customers' expectation and customers' real experience. The same thing happened to the customers' supervisors. Furthermore, this study also provides contributable evidence that the service perception gap not only exists between service provider and customers' supervisors but also exists within organization. Our results in combination with the PZB model will be helpful to the service quality improvement.