On 2020 tax return, I included my 1st Econ Impact Pymt (EIP) but NOT my 2nd EIP. My actual refund is less than the one I filed. Should I file an amended return now?

[daymikeday]

I filed electronically Feb 12th and the IRS accepted it that day. Afterwards I realized that I mistakenly hadn't included the 2nd EIP which would have reduced my refund.  I have not yet received my refund or been contacted by the IRS.
1: Should I file an amended return now or wait for the IRS to contact me?
2: Since my 2020 AGI is lower that my 2019 AGI, will the IRS use my 2020 AGI for calculating the 3rd stimulus even though my 2020 return is in limbo?

[npierson7]

No, don't amend your return until you get your refund. The IRS will reduce your refund by the amount of the second stimulus payment received. It is quite common situation and it isn't subject to penalties. If they proceed your 2020 tax return before sending the 3rd stimulus, they will use your 2020 income, otherwise they will use your 2019 income to calculate it. 

[daymikeday]

Thank you for such a helpful reply