Will your answer to missed depreciation, "put it on Schedule E, but I just label it as "481(a) Adjustment " be accepted when e-filing a 2020 return on an extension.  My 2020 return is showing an NOL in the amount of  depreciation that was missed in a 2016 return in the 11th year.  I tracked it back to the '16 tax year to see where it was coming from.