@user17709788658
Yeah, the only way to know whether TTX used the box 1 or box 2a values on a 1099-R...is to check lines 5a and 5b of the form 1040. IF your 1099-R is the first one entered, then line 5b of the 1040 "should" show the box 2a value. IF it's not the first 1099-R you've entered then you kind-of have to add things up yourself to know what should be on line 5b of the form 1040.
Since I had some after-tax contributions to my 401k, For my 1099-R , box 2a is only 0.4% lower , so it wouldn't be much of a deal if box 1 was actually used.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
