The Shirt Shop had the following transactions for T-shirts for 2018, its first year of operations:

Jan. 20 Purchased 420 units @ $ 9 = $ 3,780

Apr. 21 Purchased 150 units @ $ 10 = 1,500

July 25 Purchased 230 units @ $ 12 = 2,760

Sept. 19 Purchased 80 units @ $ 13 = 1,040

During the year, The Shirt Shop sold 730 T-shirts for $18 each. Compute the difference in GROSS MARGIN between the FIFO and LIFO cost flow assumptions