The Donut Stop acquired equipment for $21,000. The company uses straight-line depreciation and estimates a residual value of $2,600 and a four-year service life. At the end of the second year, the company estimates that the equipment will be useful for four. additional years, for a total service life of six years rather than the original four. At the same time, the company also changed the estimated residual value to $1,500 from the original estimate of $2,600. Required: Calculate how much The Donut Stop should record each year for depreciation in years 3 to 6