I received a 1099-MISC after I filed my taxes and they were accepted by the IRS. There was no additional income involved, as I had declared the amount shown on the 1099-MISC as "General Business Income" on my Schudule C, and described that income as coming from the entity sending me the very late 1099-MISC. So the total business income is unchanged, but the IRS will now see a 1099-MISC from this entity not shown as a 1099-MISC on my Schedule C, even though that income is shown as a General Business Income linked to the entity on my Schedule C. Do I need to file an amended return? Or is it okay since both the income and the entity paying it are accounted for on my Schedule C? There is no refund involved, nor additional taxes owed.
No amendment needed. If the IRS requires any clarification they will contact you.
You should not file an amended return. You reported the income. You probably won't, but if you receive a letter from the IRS because you did not "include" the 1099-MISC on your tax return, all you will need to do is respond to them in writing and explain what you just explained in your question. If you have the envelope with postmark that the 1099 came in, you might want to save it.
I just talked to the IRS help line -- they said that since there are no changes in the taxes owed and no refund involved, there is no need to file an amended return at this time. But instead, wait to see if they ask for one at some future time.