I've read through numerous Q&A's about the Line 16 "discrepancy" and see that most are resolved due to Qualified Dividends / Capital Gains being taxed differently that ordinary income. I have neither, so am still unsure why TurboTax calculates Line 16 to be about $9k LESS than the simple tax brackets * tax rates. The "Tax Smart Worksheet" has #2 "Tax Computation Worksheet" checked, and I do have Sole Proprietor losses, but I'm seeing evidence that it merely decreases my taxable income, so I'm not sure that has anything to do with the computation for Line 16.
The taxes on the Form 1040 can be calculated in various ways based on the type of income being reported on a tax return.
If your income is from wages, taxable interest, taxable dividends then your taxes on your taxable income is based on the Tax Tables in the instructions for Form 1040 starting on page 64 - https://www.irs.gov/pub/irs-pdf/i1040gi.pdf#page=64
My income is greater than $100k but contains neither taxable interest nor taxable dividends, nor anything from Schedule D, Schedule J, Form 8615, or the Foreign Earned Income Tax Worksheet; so the calculation should be a simple calculation as shown on Page 76 (Section B).