Rev Proc 2004-11, which said:

SECTION 4. WAIVER OF TWO-YEAR RULE IN REV. RUL. 90-38
.01 In general. Notwithstanding Rev. Rul. 90-38, a taxpayer may file a Form 3115 under Rev. Proc. 97-27, 1997-1 C.B. 680 (or its successor), or Rev. Proc. 2002-9, as applicable, to change from an impermissible method of accounting for depreciation to a permissible method of accounting for depreciation under § 1.446-1T(e)(2)(ii)(d) for any depreciable or amortizable property subject to § 1.446-1T(e)(2)(ii)(d) and placed in service by the taxpayer in the taxable year immediately preceding the year of change (as defined in section 5.02(2) of Rev. Proc. 97-27 or section 5.02 of Rev. Proc. 2002-9, as applicable) (hereinafter, this property is referred to as “1-year depreciable property”), provided the additional term and condition in section 4.02 of this revenue procedure is satisfied. Alternatively, the taxpayer may make the change from the impermissible depreciation method to the permissible depreciation method for the 1-year depreciable property by filing an amended federal tax return for the placed-in-service year prior to the date the taxpayer files its federal tax return for the taxable year succeeding the placed-in-service year.

So that was only when the mistake was caught in the first year. But then it was rescinded by Rev Proc 2007-16, which allows amended returns for earlier years but still requires the filing of a 3115. At least, that’s how I read its Section 3, but I haven’t had any coffee yet this morning.

This whole 3115 shtick is a ridiculous anachronism which should only apply to taxpayers with a net worth of, say, more than $10 million. If anyone at IRS took it seriously, they would deregulate it.