Hard to know....could be one of these, or something indescribbable.
1) TTX uses the AGI from the "originally-filed" and accepted Federal tax return, not from a later amended tax form.
2) Some folks file and get their taxes done, then come back do something in their file that changes thing....and messes up the AGI.
3) Some folks have two accounts, and use a different account this year...not the one they used to file last year. i.e. there's no connection between the two.
4) Some folks fail the e-file, and then print-file on paper by mail. Then the AGI needs to be set as-if it was zero for the prior year. (as far as being able to e-file this year is concerned )
or...who knows..
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
