A machine costing $213,200 with a four-year life and an estimated $18,000 salvage value is installed in Luther Companys factory on January 1. The factory manager estimates the machine will produce 488,000 units of product during its life. It actually produces the following units: 121,600 in Year 1, 123,900 in Year 2, 120,700 in Year 3, 131,800 in Year 4. The total number of units produced by the end of Year 4 exceeds the original estimatethis difference was not predicted