OfficeSupplies Ltd. uses a periodic inventory system. It entered into the following transactions for May:

Date	Description	Units Acquired at Cost	Units Sold at Retail
May 1	Beginning Inventory	200 units @ $45 per unit
May 7	Purchase	500 units @ $48 per unit
May 14	Sale		450 units @ $75 per unit
May 21	Purchase	350 units @ $50 per unit
May 28	Sale		300 units @ $80 per unit

For specific identification, the May 14 sale consisted of 100 units from beginning inventory and 350 units from the May 7 purchase. The May 28 sale consisted of 150 units from the May 21 purchase and 150 units from the May 7 purchase.

Required:

1. Calculate the ending inventory and COGS using FIFO and LIFO methods.
2. Determine the gross profit for May using the weighted average cost method.
3. Assess the financial impact of each inventory costing method on OfficeSupplies Ltd.'s net income.
4. Provide strategic recommendations for inventory management based on the financial analysis.