The Shirt Shop had the following transactions for T-shirts for Year 1, its first year of operations. January 20 Purchased 470 units @ $ 7 = $3,290 April 21 Purchased 270 units @ $9 = 2,430 July 25 Purchased 350 units @ $12 = 4,200 September 19 Purchased 160 units @ $14 = 2,240 During the year, The Shirt Shop sold 1,020 T-shirts for $23 each. c. Compute the difference in gross margin between the FIFO and LIFO cost flow assumptions.