can someone please help me understand what the 4th period is asking me, thanks in advance

A machine costing $216,000 with a four-year life and an estimated $20,000 salvage value is installed in Luther Company's factory on January 1. The factory manager estimates the machine will produce 490.000 units of product during its life. It actually produces the following units: 121,900 in Year 1. 124.000 in Year 2.120,500 in Year 3.133.600 in Year 4. The total number of units produced by the end of Year 4 exceeds the original estimate--this difference was not predicted. (The machine cannot be depreciated below its estimated salvage value.) Required: Compute depreciation for each year (and total depreciation of all years combined) for the machine under each depreciation method. (Round your per unit depreciation to 2 decimal places. Round your answers to the nearest whole dollar.) Complete this question by entering your answers in the tabs below. Units of Production DDB Straight Line Compute depreciation for each year (and total depreciation of all years combined) for the machine under the Units of production Complete this question by entering your answers in the tabs below. Straight Line Units of Production DDB Compute depreciation for each year (and total depreciation of all years combined) f production. Year Units per unit 1 2. 121,900 124,000 120,500 133,600 Units of Production Depreciable Depreciation Depreciations Units Expense 121,900 $ 0.40 $ 48,760 124,000 $ 0.40 49,600 120,500 $ 0.40 48,200 $ 0.40 $ 366,400 $ 146,560 3 4 Total Straight Line Units of Production DDB Compute depreciation for each year (and total depreciation of all years combined) for the machine declining-balance. End of Period Year 1 DDB Depreciation for the Period Beginning of Period Book Depreciation Depreciation Rate Value Expense $ 216,000 50% $ 108,000 108,000 50% 54,000 54,000 50% 27,000 27,000 50 % 189,000 Accumulated Book Value Depreciation $ 108,000 $ 108,000 162,000 54,000 189,000 27,000 27,000 2 3 4 Total