Company acquired a plant asset for $9000 January 1, 2011 and appreciated the equipment by using the straight-line basis over a 12 year. With no scrap value. On January 1, 2019 after using the asset for eight for years, the company believes of the asset will be productive for an additional eight years, As opposed to four years. The increase in useful life results from an improved maintenance program initiated two years ago. How should company report this change an estimate?

Annual depreciation is X per year before the change in estimate. The revised depreciation is X per year. Company does not make any changes to or must re-state prior financial statements?

What are the a dollar amounts for the two X's? And does the company not make any changes or restate financial statements?