If you click the "edit" button at the top of the business summary on the dashboard, you will be land on the business projection detail screen.
On the right you will see blanks to override the projected amounts. Any amount you enter there and then save, will be used in the projection instead of what the software calculated (middle column).
If you scroll to the bottom of the page, you will find several other settings that can be used to further customize your projection. Three of the most important are the Payroll, Fixed Asset, and Specified Service Business entries that relate to the Sec 199 A Deduction.
For more about the Sec 199A Deduction click here.