Will I have to file an amended return if I reported a 1099-INT income amount $20 greater than it was? My interest was actually below $10 minimum

No, if you over-reported this income, you don't need to file an amended return -- it's entirely your option, and may not be worth your time.

Thank you for your response! I e-filed our return on March 9th and our refund has not yet been approved. Our return is substantial due to very low income last year and EIC and child tax credits for 4 children. I have wondered if reporting checking account interest so high in error has delayed the refund approval. I would love to avoid filing an amended return but wanted to handle the situation ethically and also avoid reason for audit in the future.