Is there a reason that the total of the ‘Investments and Savings’ portion of my income isn’t adding up correctly?

I'm not sure what specific issue you are having with that worksheet. However, you can view your Form 1040 lines 2,3 and 7 to see if they list the correct interest, dividends and net capital gain income or loss. If those amounts are correct your tax return is accurate as far as your investment income is concerned.

To view your form 1040 and schedule 1 to 3:

1. Choose Tax Tools from your left menu bar in TurboTax Online while working in your program
2. Choose Tools
3. Choose View Tax Summary
4. See the Preview my 1040 option in the left menu bar and click on it
5. Choose the Back option in the left menu bar when you are done