Please help with the last three entries and explain why

Wildhorse Co. purchased equipment on March 27,2018, at a cost of $292,000. Management is contemplating the merits of using the diminishing-balance or units-of-production method of depreciation instead of the straight-line method, which it currently uses for other equipment. The new equipment has an estimated residual value of $4,000 and an estimated useful life of either four years or 80,000 units. Demand for the products produced by the equipment is sporadic so the equipment will be used more in some years than in others. Assume the equipment produces the following number of units each year: 14,200 units in 2018; 20,200 units in 2019; 20,600 units in 2020; 20,000 units in 2021; and 5,000 units in 2022. Wildhorse has a December year end Double-diminishing-balance method: Opening Carrying Carrying Depreciation Expense Accumulated Depreciation Year Amount Amount $ 292,000 2018 $ 109500 292,000 109500 182500 2019 182500 91250 200750 91250 2020 91250 246375 45625 45625 2021 22813 22812 45625 269188 2022 22812