Using the Step-by-Step method (using same values in original post) served to find more bugs in TurboTax and validate the erronous entry on Line 4(b) on the generated Form W-4. Line 4(b) should be blank on the generated Form W-4, but it appears the Credits value from Step 3 is carried to Step 4, Line 4(b). The second bug is the Step-by-Step generated a Form W-4 with 'Single or Married filing separately' checked [Step 1(c)] when this return was filed as 'Head of household'. What does it take for Intuit to acknowledge these bugs????
