Amending an old return

I did my 2018 taxes calculating all my gains/losses using FIFO by hand. I’m working on my 2021 taxes using CoinTracker (which is INSANELY easier) and using HIFO. I’m mostly confident there is no overlapping units between the 2018 FIFO and 2021 HIFO batches of crypto.

I want to buy CoinTracker for the 2018 year and amend my past tax return using HIFO. I think the results for me will be better (and more accurate) than my FIFO method. Is CoinTracker smart enough to handle what I’m attempting? Will it know that I did 2021 using HIFO and then make sure there are no overlapping units when I go backwards to do the 2018 transactions?