You don’t have to file an amended return or contact the IRS. The IRS will contact you by mail and ask that you send the schedule. The IRS letter will have instructions on where to mail it.
Depreciation methods that allow faster write-offs than straight-line rates in the earlier periods of the useful life of an asset. For example, in the first few years of recovery, MACRS allows a 200% double declining balance write-off, twice the straight-line rate.