I agree with your MAGI calculation, RayW7, but TurboTax is excluding non-taxable SS benefits from my MAGI on Form 8960 (Net Investment Income Tax - NIIT). Instead, it's using my AGI amount (and NOT adding in the 15% of my SS income that isn't taxable). Thus, it's under-calculating my NIIT. This is such a clear error I find it difficult to believe it's occurring.
