The present study investigates a company's procurement process with a weak performance measurement and management system in its supply chain. The challenge in evaluating the customer-specific engineer-to-order projects in the case company prompted the use of SCOR modelling as a standardization tool to analyze the supply chain processes and metrics. The selection of performance metrics is a dynamic process that needs to be updated based on changing company needs. However, the complex relationships between metrics make it difficult for stakeholders to predict their impact on results. To address this, we utilized scenario-based Fuzzy Cognitive Maps to prioritize important SCOR metrics and fuzzy numbers in our evaluations to account for the inherent fuzziness in procurement processes. To the best of our knowledge, this is the first study to evaluate the trade-offs between procurement performance metrics using SCOR modelling.