I realized my 2017 income was incorrect when I was filing my 2018 taxes
So after amending your 2017 return you need to start over with your 2018 return from scratch, in order to import the updated information from the 2017 return into the 2018 return.
Now if the absolute only thing you did when you amended your 2017 return was add another W-2, with *rare* exception that changes nothing for your 2018 return. So there's no need to start the 2018 return over and import the data again.
However, when you e-file the 2018 return you may need to use the AGI from your 2017 return from BEFORE you amended it.
