This advice is contradictory to the advice given in the link below. Box 1 should be either contribution + earning or contribution - loss. Box 2a should be 0 in case of loss (negative net attributable ) or the earning incase of a positive net attributable.
https://www.google.com/amp/s/ttlc.intuit.com/community/tax-credits-deductions/discussion/excess-roth...
