Garonne Co., a calendar year-end firm, has used the FIFO method of inventory measurement since it began operations in Year 3. Garonne changed to the weighted-average method for determining inventory costs at the beginning of Year 6. Justification for this change was that it better reflected inventory flow. The following schedule shows year-end inventory balances under the FIFO and weighted-average methods: In its Year 6 financial statements, Garonne included comparative statements for both Year 5 and Year 4. What adjustment, before taxes, should Garonne make retrospectively to the balance reported for retained earnings at the beginning of Year 4? What amount should Garonne report as inventory in its financial statements for the year ended December 31, Year 4, presented for comparative purposes? By what amount should cost of sales be retrospectively adjusted for the year ended December 31, Year 5