No, you definitely do not add the Roth 401(k) under Deductions and Credits. You only list the box 12, code AA from the W2.
A Roth 401(k) is not an IRA, and is also not deductible. The only benefit you can get from this on your tax return is the Retirement Savings Credit. If your income is low enough to qualify for this credit, Turbo Tax will automatically know just from input of the W2.
All you need to do is enter your W2 exactly as it appears.
