For real property placed in service after 1986, depreciation under the MACRS system is calculated using the straight-line method and a half-year convention in the year of acquisition and in the year of disposition. 200% DB method and a mid-month convention in the year of acquisition and in the year of disposition. straight-line method and a mid-month convention in the year of acquisition and in the year of disposition. 200% DB method and a half-year convention in the year of acquisition and in the year of disposition.