@Waterl wrote:
Thank You in advance for your thoughts!
My thoughts are as follows:
There are definitely benefits to the De Minimis Safe Harbor Election but, pursuant to Treas. Reg. §1.263(a)-1(f)(5), you must attach a statement for the election to your timely filed original federal tax return including any extension for the taxable year in which the amounts subject to the election are paid.
Consequently, you cannot simply amend your prior year tax returns because changing the treatment of an item or items on those returns would be a change in your method of accounting and that would require filing Form 3115, which is something you do not want to attempt without professional tax guidance (it is not a DIY project).
At this point, it probably does not need to be stated that you cannot include foregone amounts from previous tax years on your 2018 income tax return.
See generally https://www.irs.gov/businesses/small-businesses-self-employed/tangible-property-final-regulations
