Retirement tax questions

Thank you so much.  I did download my 2018 return and it shows the basis (incorrectly) as $6,500 (line 14 of 8606) but also shows there was no taxable amount.  I think I may only need to correct the basis in the 2020 return, and not worry about amending the 2018 return since it resulted in no tax liability.  Do you agree with that approach?