Other than failing to select code 4 for one of the box-7 selections and code D for the other, I don't know of any way you can cause TurboTax to treat the taxable amount of this Form 1099-R as anything other than the amount in box 2a. The amount that you specify as RMD doesn't matter. the date of birth of the decedent doesn't matter. Just confirm that the amount on line 5a of Form 1040 includes the gross amount from box 1 of the Form 1099-R and line 5b includes the taxable amount from box 2a.
