TurboTax's program is designed to start you with the shorter forms, no matter which version you start in. Then, depending on your entries, it will automatically switch you when appropriate. This takes the guess work completely out of your hands.
Rest assured that if TurboTax filed your return with the longer form, it was because you had something in your return that required it or it served to provide you with a tax benefit (like having enough deductions to fully itemize.)