Warning - Cannot amend taxes after entering payment info

I wanted to post a PSA in case this helps anyone.

 

I just finished filing my taxes with TurboTax after a great deal of frustration.  I filled everything out, double checked, and ran the Turbotax review function.  Everything looked great and I proceeded to enter my payment information.  I got to the screen that allows me to download the PDF of my return - and I did so, for my records.  I looked at the PDF a final time - and discovered a mistake!  Good thing I checked!  No problem, I'll just fix the mistake before I file.

I went back to Tax Home and edited the relevant sections, but I did not see my return amount change.  The 1040 form did not change.  
I spent about 4 hours, cumulatively, on several calls with three different agents (All very helpful!  No complaints there.)  We tried deleting forms, re-entering forms, and quadruple-checked my information.  Nothing affected the needed changes to my 1040. We even tried to wipe the entire tax form and start completely over -

but TurboTax does not allow you to start over once you've entered payment information.

We came to the following conclusion:  Once I passed the Payment screen, Turbotax locks in certain forms and doesn't allow them to be deleted or altered.  You can re-enter information all you want, but those forms are immutable.  I couldn't go back, I couldn't start over, and I couldn't very well submit a bad tax return.  

 

The solution was ultimately to create a brand new account and start from scratch.  This worked fine, and I was able to avoid my first mistake, and filed successfully.  

 

I promised the TurboTax support crew that I would post here so this issue is documented.  Learn from my mistake:  Do not enter your payment info until you are 100% certain that the return is correct!  You cannot review the PDF you download at the end and go back to fix mistakes.  

I hope this helps someone.