@NCperson
I think you’re only half right here. A return filed before the deadline is deemed to have been filed on the deadline. Yes, in a normal year, a return filed June 30 with a valid extension to October 15 is deemed filed on June 30. But since the official deadline for 2019 was July 15, any return filed before July 15 is deemed filed on July 15.
Generally, for a credit or refund, you must file Form 1040-X within 3 years (including extensions) after the date you filed your original return or within 2 years after the date you paid the tax, whichever is later. If you filed your original return early (for example, March 1 for a calendar year return), your return is considered filed on the due date (generally April 15). However, if you had an extension to file (for example, until October 15) but you filed earlier and we received it on July 1, your return is considered filed on July 1.
