I made an error in depreciation for 2018, 2019, 2020. Does this mean I can amend those three years? I heard about form 3115 being needed if a change needs to be made prior to 3 years. I then hear about the "2 year rule". I am confused as to when the 3 years back start. Essentially, I did it incorrectly for 3 years straight and was wondering if I need form 3115 or it is just a simple amendment?
Thank you.
