Deductions & credits

DS30 said that if the foreign tax refund only affects the carryover amount, then it is not necessary to file an amended return. I need some clarification here. I have lived in and paid taxes to a country in Europe since 2015. I did not claim any foreign tax credit for 2015, 2016, and 2017 because I owed no USA tax. I did not realize there was a carryforward provision. In 2018 and 2019, I recorded the foreign tax "paid or accrued" and offset this against a very tiny USA tax liability for each of those two years. Subsequently, I received large tax refunds from the foreign country, but i have still paid far more foreign tax than the two tiny USA tax liabilities already mentioned. I have all the documents to substantiate this. Can I simply make the lump sum adjustment in 2020 so as to make the total 2015-to-date carryforward correct? I owe zero USA tax for 2020, so I will not use any of the carryforward for 2020.  I really want to avoid filing amended returns. That is very time-consuming and expensive, especially since there will be zero effect on my USA taxes. Finally, the form seems to indicate that I can carryforward 10 years of foreign taxes paid. It that correct? Thanks!