Shellhammer Company's inventory records show the following data for the month of September: Units 100 Unit Cost Inventory, September 1 $3.34 Purchases: September 8 3.50 September 18 350 3.70 A physical inventory on September 30 shows 200 units on hand. 450 a. Calculate the value of ending inventory and cost of goods sold if the company uses FIFO inventory costing and a periodic inventory system. b. Explain briefly which inventory valuation method is more acceptable and why.