There are a bunch of answers on Chegg but none of them explain how you get the Current Period's Layer in order to calculate Estimated ending inventory at cost for LIFO

Required information (The following information applies to the questions displayed below.) Raleigh Department Store uses the conventional retail method for the year ended December 31, 2019. Available information follows: a. The inventory at January 1, 2019, had a retail value of $52,000 and a cost of $39,960 based on the conventional retail method. b. Transactions during 2019 were as follows: Gross purchases Purchase returns Purchase discounts Gross sales Sales returns Employee discounts Freight-in Net markups Net markdowns Cost Retail $356,160 $560,000 6,600 17,000 5,700 551,500 8,000 2,500 30,000 32,000 17,000 Sales to employees are recorded net of discounts. c. The retail value of the December 31, 2020, inventory was $71,070, the cost-to-retail percentage for 2020 under the LIFO retail method was 76%, and the appropriate price index was 103% of the January 1, 2020, price level. d. The retail value of the December 31, 2021, inventory was $52,470, the cost-to-retail percentage for 2021 under the LIFO retail method was 75%, and the appropriate price index was 106% of the January 1, 2020, price level. Required: 2. Estimate ending inventory for 2019 assuming Raleigh Department Store used the LIFO retail method. (Amounts to be deducted should be indicated with a minus sign.) Answer is complete but not entirely correct. Cost Retail Cost-to- Retail Ratio $ $ 52,000 560,000 39,960 356,160 30,000 (6,600) (5,700) OOO Beginning inventory Add: Purchases Add: Freight-in Less: Purchase returns Less: Purchase discounts Add: Net markups Less: Net markdowns Goods available for sale (excluding beginning inventory) Goods available for sale (including beginning inventory) (17,000) 32,000 (17,000) 558,000 610,000 373,860 413,820 $ Cost-to-retail percentage 67% $ Less: Net sales Sales Sales returns Employee discounts Estimated ending inventory at retail Estimated ending inventory at cost 551,500 (8,000) 2,500 (546,000) 64,000 S $ 42,880