In the scenario where an ABC telecom customer orders additional services that can be supported by existing equipment (like a router supporting multiple internet bundles), the "Downstream Order Item Scope" is the most appropriate. This scope ensures that the decomposition process generates Fulfillment Request Lines (FRLs) considering the existing inventory item, avoiding unnecessary provisioning of new equipment and leveraging existing assets efficiently.References:Salesforce Communications Cloud documentation on product modeling and order management processes.