Cost Allocation Tags allow an organization to assign metadata to resources, which enables a detailed organization of billing information. This is instrumental for departmental cost tracking and enables precise reporting necessary for budget management. These tags, when associated with the Cost and Usage Report, give a granular view of costs, which is what the question is targeting. Setting custom budgets with alerts helps manage costs but does not provide the granular allocation of expenses by department. Monitoring cost patterns over time does not help with the direct allocation of expenses that the question requires. Billing Conductor focuses on billing customization for client invoicing or resale rather than for internal departmental reporting and cost control.