Retail Inc. uses the FIFO cost formula in a perpetual inventory system. Below is the inventory record for September, 2021: Beginning inventory 20 units @ S19 per unit Purchases Sep 1 Sep 7 Sep 8 70 units @ $20 per unit Sales 50 units @ $30 per unit Sep 9 Sales 25 units @ $31 per unit Sep 10 Purchases Sep 22 50 units @ $22 per unit Sales 40 units @ $28 per unit If Retail Inc. used the average cost formula instead of FIFO, gross profit from the September 8 sale would be cannot be determined. lower. higher. the same.