So why not amend just 2019 and claim the Section 481 adjustment on it for 2018? Assuming the 2020 return has not yet been filed, because otherwise why would someone be asking about it? But even if it has been, what rule is violated by amending it, since it is the first year the accounting rule has been broken now that the 2018 and 2019 errors have been purged. Either that, or make the Section 481 adjustment on the 2021 return.

The Form 3115 is like an Alien Tax Clearance. Sure, it’s required, but if everyone complied then IRS would have no time for anything else. It’s a joke, but on a profession with no sense of humor (at least, outside of northern Minnesota).

I think it was suggested elsewhere that the Section 481 deduction can be claimed for cumulative errors going back to closed years. I don’t think that’s correct, but I suppose you can try to get away with it. Section 481(a) mentions only the “preceding taxable year,” and I think what they are getting at is a change from cash to accrual, or FIFO to LIFO, for example.