I just tried a test of the 2019 Turbo-tax What-if Worksheet. First I created net taxable income line 43 at $80,000.
Then I reduced that net taxable income by $1,000 to $79,000 and tax due went down $120 or 12%
Then I increased that net taxable income by $1,000 to $81,000 and tax due went up $270 or 27%
Thus it seems clear that the What-if Worksheet has the correct tax rate of 12% for incomes below
$80,000 and the incorrect tax rate of 27% for income above $80,000...That rate should be 22%..
By the way the actual increase in rates to 22% should happen at $80,251 ..which is another error
as it happens now at $80,000...
