Required information [The following information applies to the questions displayed below.] The Shirt Shop had the following transactions for T-shirts for Year 1, its first year of operations: January 20 April 21 Purchased 370 units Purchased 140 units $12 = $13 - $ 4,440 1,820 July 25 Purchased 220 units $15 3,300 September 19 Purchased 100 units @ $16 - 1,600 During the year, The Shirt Shop sold 690 T-shirts for $21 each. b. Compute the difference in gross margin between the FIFO and LIFO cost flow assumptions. Gross margin FIFO LIFO Difference.