This study examined the effects of extending a model of customer satisfaction with a construct of perceived sustainability. It thus adds empirical data to the theoretical assessment of a more holistic and socially aware customer, whose satisfaction is dependent on the customers' perceived idea of their supplying organization as sustainable. Utilizing the Extended Performance Satisfaction Index (EPSI) model as well as the Partial Least Square Path Model (PLS-PM) technique, a comparison was performed to examine changes in explanatory and out-of-sample prediction power between the extended and original models. The data comprise 4518 business-to-business (B2B) and business-to-consumer (B2C) interviews conducted in the Swedish banking and energy sector during 2022. Favorable metrics indicate the value of including perceived sustainability within the EPSI model. The results demonstrate a positive relationship between perceived sustainability and customer satisfaction. Overall, the customers' idea of a perfect/ideal organization has the largest increase in out-of-sample predictionary power when adding the construct of perceived sustainability. As such, the customer sees an ideal/perfect organization as someone that can both deliver a functional product and do it in a sustainable way. The study concludes that organizations in the studied sectors, that are perceived to fulfil this criterion will be rewarded by higher customer satisfaction.