BioHealth Technologies uses a periodic inventory system. It recorded the following inventory transactions for June:

• June 1: Beginning Inventory, 250 units @ $90 each
• June 8: Purchased 400 units @ $92 each
• June 15: Sold 500 units @ $140 each
• June 22: Purchased 350 units @ $95 each
• June 28: Sold 400 units @ $150 each

Specific identification details: The June 15 sale consisted of 100 units from beginning inventory and 400 units from the June 8 purchase. The June 28 sale consisted of 200 units from the June 22 purchase and 200 units from the June 8 purchase.

Required:

1. Compute the ending inventory and COGS using specific identification and FIFO methods.
2. Calculate the gross profit using the LIFO method.
3. Evaluate the impact of different inventory costing methods on BioHealth Technologies' financial statements.
4. Recommend an inventory costing method considering BioHealth Technologies' business strategy and market conditions.