Operates on Service Orders, shown in the Zuper client app as "Work Order" (in every industry). Work Orders share the exact same underlying schema and endpoints as Purchase Orders / Material Orders; they're distinguished only by the purchase_order_type field (SERVICE_ORDER here) and the /service_orders route prefix. Creates multiple orders in one call. Each item in purchase_orders uses the exact same field shape as the single Create endpoint's purchase_order object (see Create Purchase Order / Create Work Order), just without the outer wrapper key.