The problem was a glitch in the TurboTax program:
On the Personal Income section, Box 12a-d, the dropdowns don't always update when selected. I had mistakenly selected "A-Uncollected social security..." When I re-selected "D-Elective deferrals to 401(k), it looked selected, but when I went back later to research the tax discrepancy, I was that it had not retained the "D" selection.
I tested this several times and found that about 50% of the time it does NOT update properly.
User beware!
