Will TurboTax update my IRA Deductions and other deductions/penalties if I add other sources of income later?

[DoninGA]

You can enter, change or delete anything in your tax return at any time when using TurboTax before filing the tax return.

[Opus 17]

After you transmit your return, no changes can be made except by filing an amended return.

However, before you file, you can work on your tax return in any order, and the program will update itself every time you change something. So the answer is Yes.  The program will update your figures every time you change something, and it will also do a separate full review before you actually file.