The asset is depreciated uniformly over the specified total useful life. Post-capitalization and subsequent acquisitions necessitate an increase in depreciation, by the amount which would have been necessary to fully depreciate the addition over the original useful life of the asset. This results in an increase in the length of time necessary to depreciate the asset, that is, the time period from the beginning of depreciation until the book value of zero is reached.

Calculation :

Depreciation = APC / expected useful life

An internal calculation key (for example 1041), which determines a percentage rate from expected useful life and bases asset values on the acquisition value or replacement value, characterizes this depreciation method. Furthermore, certain calculation keys allow depreciation below book value zero after the planned life has expired.

In this case, the rate of depreciation can decrease after the planned life because you can then use the already expired useful life instead of the planned expected useful life to calculate depreciation. In the 11th year of use, you would not calculate with 10% as in the preceding 10 years, but only with 1/11 = 9.0909%.