Calculate the cost of goods manufactured (COGM) using the FIFO (First-In-First-Out) costing method, with the following data: beginning work in process inventory of $25,000, direct materials used of $40,000, direct labor of $30,000, manufacturing overhead of $20,000, and ending work in process inventory of $15,000. Elaborate on the FIFO costing method and its suitability for inventory valuation. Provide detailed calculations and insights.