The Shirt Shop had the following transactions for T$-$shirts for Year $1,$ its first year of operations.

January $20$ Purchased $410$ units @ $ $9=$ $$3,690$

April $21$ Purchased $210$ units @ $$11=2,310$

July $25$ Purchased $290$ units @ $$14=4,060$

September $19$ Purchased $100$ units @ $$16=1,600$

During the year, The Shirt Shop sold $840$ T$-$shirts for $$25$ each.

c$.$ Compute the difference in gross margin between the FIFO and LIFO cost flow assumptions.