A manufacturing company adopts the weighted average costing method to calculate the cost of goods manufactured (COGM). With the following data: beginning work in process inventory of $15,000, direct materials used of $25,000, direct labor of $20,000, manufacturing overhead of $18,000, and ending work in process inventory of $10,000, compute the COGM. Elaborate on the weighted average costing method and its applicability in inventory valuation. Provide detailed calculations and insights.