ADDENDUM:
Also, here's how you can confirm what method TurboTax is using to calculate your tax. Go into Forms Mode and bring up the Form 1040 Worksheet. On that Worksheet scroll down to between lines 15 and 16, and you should see a Tax Smart Worksheet which shows what computation method or methods TurboTax used. It may simply show that it used the QDCGT Worksheet, but sometimes it can use more than one method depending on items in your return.
