That makes slightly more sense, but I still don't know why you think you would need to amend. If the IRS changes something, the changes are all done, and there is no need to amend.
The "change in accounting method" doesn't DIRECTLY allow the IRS to go past 3 years. However a "substantial understatement of tax" does allow them to go past 3 years. If they disallow an unauthorized "change in accounting method", that could create the "substantial understatement of tax".
