Do you have code G in box 7? If yes, then TurboTax should ask you the following questions after you entered the 1099-R :
If you have other codes then you should see these follow-up questions in TurboTax Desktop:
In TurboTax Online:
I have a similar situation (it's a part of my 403b that I rolled over into a Roth IRA).
But I have already entered the 1099R (with a G in box 7). I don't remember for sure if it asked me those questions and what I answered. But if it asked, I must have answered as you suggested. But I do not see a form 8606 in my list of forms. Should it have generated a 8606?