I assume you are looking at the Form 8615 Schedule D Tax Worksheet. That's where the tax on Form 8615 line 9 is calculated. TurboTax always uses the Form 8615 Schedule D Tax Worksheet just to simplify its calculations a bit. As long as line 11 of the Form 8615 Schedule D Tax Worksheet is zero, i.e. there is no 28% Rate Gain or Unrecaptured Section 1250 Gain, the result is the same as if the Qualified Dividends and Capital Gains Tax Worksheet were used, and it avoids having to have a separate worksheet in the TurboTax software.
The TurboTax help for the Form 8615 Schedule D Tax Worksheet says "The program always uses the Schedule D Tax worksheet for the computation regardless if there is any 28% rate gains or 1250 unrecaptured gains since it is all inclusive."
