Bonita Watch Company reported the following income statement data for a 2-year period. Bonita uses a periodic inventory system. The inventories at January 1, 2021, and December 31, 2022, are correct. However, the ending inventory at December 31,2021 , was overstated $6,000. What is the cumulative effect of the inventory error on total gross profit for the 2 years? Cumulative effect of the inventory error $