Chang Industries has 1,200 defective units of product that have already cost $13.20 each to produce. A salvage company will purchase the defective units as they are for $4.20 each. Chang's production manager reports that the defects can be corrected for $6.80 per unit, enabling them to be sold at their regular market price of $19.40. The incremental income or loss on reworking the units is: