Amazon.com, Inc. operates numerous fulfillment centers worldwide. The company is eager to allocate overhead costs accurately for performance evaluation. Total overhead costs for the period stood at $25,000,000. The cost accountant identified several cost drivers including facility size, number of orders processed, and miles traveled for delivery. Additionally, indirect costs related to utilities, maintenance, and administrative expenses need to be considered. Develop a robust cost allocation methodology that takes into account the unique characteristics of each fulfillment center. Propose performance metrics to assess operational efficiency while ensuring fairness and transparency in cost allocation.