Thanks for the follow-up on why it's more complicated to handle scenarios where the after-tax was included in the 401k balance. I understand that it may then difficult to craft an elegant solution to the problem.
My concern remains that there isn't any warning when I enter the form that it won't be correctly handled by TurboTax nor any hint on what actions I might need to to resolve the problem. TurboTax knows that I entered a form with the both the box 1 (gross) and box 2 (taxable) having values, along with the distribution code G. I was able to realize the issue with the tax calculation as I stepped thru the questions after entering the 1099-R, as I was seeing how the tax due calculation was changing (or not changing) depending on how I answered it. It either taxed the whole amount or none of it. The gotcha was no answer would allow it to correctly calculate the tax without splitting the form, as you've already pointed out. Now, I caught it because the values were significant enough for me to notice, but I don't know if every user of TurboTax would see and understand the implications.
Shouldn't TurboTax at least present a warning or some other notification that it can't correctly handle the form as entered, without it blindly accepting it without any warning? Perhaps with a pointer to what must be done to split the form apart. What happens now is the user must be astute enough to recognize there is a problem and then go searching the community site hoping there is an answer available.
I will grant you that I did not get all the way to running the final tax checks and maybe it would have warned that it was incorrect at that time. However, I believe it is normally better to warn a user during the entry of a form if there is a problem rather than waiting until the end (or maybe not at all, as I didn't test to see if it would ever catch the mistake).
Thanks again for all your input.
