Thanks Carl. I understand the depreciation the way you do. Since it was fully depreciated before my Dad's passing, the only recapture on the depreciation is the new depreciation taken from date of death in Nov 2017 to date of sale in 2020. From what I see, Turbo Tax calculates that depreciation when I enter in the 1/2 new asset etc... and report as sale. So it seems like the only advantage to going back to fix the depreciation from previous years is to take the depreciation off the tax bills for those years. If I wave the white flag and give that up, why bother with the 3115 form for accounting change? I guess my question put simply is if there is a way to just do the sale in Turbo Tax for 2020 in such a way that it will calculate the tax owed, correctly, with the new depreciation from the new basis. It looks like TT's calculations will recapture the depreciation in the sale anyway on the new basis.
I'll likely get a tax expert to review and go forward, but it's going to be hard to find someone this late and this was a late finding on our end.
