TurboTax's labeling of the entry boxes is misleading. Roth contributions are not a deferral of income, so TurboTax's labeling of the Roth 401(k) regular contribution box as "Elective Deferrals" is misleading. It should be labeled "Regular Contributions." The labeling of the first section as "Individual 401(k)" is also misleading. This section is for pre-tax contributions only (true elective deferrals and employer contributions). The section labeled Roth 401(k) is for any contributions to the designated Roth account in the individual 401(k).
What TurboTax means when it says that is that Roth contributions to the individual 401(k) are not reported on your tax return is that they are not deductible as a self-employed retirement deduction on Schedule 1 line 15, the only place on your tax return the reports anything about your contributions to the individual 401(k).
If you made a $5,000 elective deferral and a $10,000 Roth contribution, $5,000 goes in the "Individual 401(k)" "Elective Deferral" box and $10,000 goes in the "Roth 401(k)" "Elective Deferral" box. The $10,000 must be entered to allow TurboTax to determine if the the $15,000 total exceeds your net earnings.
