Wait, how did you "add" your 401(k) in a way that reduced your AGI? Are you self-employed and you made contributions to a self-employed 401(k)?
If you are an employee who received a W-2, enter amounts shown in box 12 of your W-2 only in box 12 of TurboTax's W-2 form, nowhere else in TurboTax.
A 401(k) is not an IRA. A deductible IRA contribution would be a contribution you personally make to a traditional IRA outside of any retirement contributions you make through your employer's retirement plan.
