How to setup a pretax Deduction

I'm trying to setup a pretax deduction but it does not seem to be calculating correctly.

• Munis 
• Payroll Exceptions

1. Go to the payroll Exceptions program. (Human Resources/Payroll>Payroll>Payroll Setup>Deduction and Benefit Master click on Exceptions in the Menu.)
2. Click Search. Define Tax deduction (Example Federal Income Tax, deduction 3000). Click Accept.
3. Click direction arrows to navigate to Processing Code 2-No deductions are exempt except.
4. Click Update. TAB down to Exclusion Ranges and define deduction to be excluded. Click Accept. 
5. Do steps 2-4 for each deduction where pretax deductions need to be added.

Deduction was not included in the exceptions for tax deductions.