Since service has evolved as a third factor that customers consider besides quality and price when making buying decisions, design for ease of service has been proposed in pursuing service excellence and gaining customer loyalty. Its approach includes a service performance assessment in which service time and complexity of service delivery have been considered to form a service index to reflect the service supportability of a design. To make service operations easier, not only should the complexity and time be taken into account, but the quality of timely service delivery is also critical. This paper presents the integration of the quality aspect of service into the index to ensure service supportability. This integration is built around the idea that poor service performance almost always results in customer dissatisfaction; therefore, a design should ensure customers will not be dissatisfied with service delivery. For each service activity, potential causes of poor service performance and their effects on customer dissatisfaction are identified and assessed. A Reverse Kano model is applied to determine how customers perceive the potential causes. The information gathered is incorporated into the index in the form of a no dissatisfaction factor. The proposed index was applied to assess window frame installation for illustration.