Dropping in to provide some insights, alex-pearce.

Yes, you'll want to create deduction item to reduce the amount. 

Here's how to do it:

1. In the employee set up, click the Add a new deduction link under Does [employee name] have any deductions? (Examples: retirement, health care).
2. Choose Deduction/contribution under Deduction/contribution or garnishment drop-down.
3. Under Deduction/contribution drop-down, choose New deduction/contribution.
4. Under Deduction/contribution type, choose Other deductions.
5. Under Type, choose Other after tax deductions.
6. Enter a Description or name of the deduction item, and then enter the amount per pay period.
7. Click OK.

The Community is always here for you if you have other payroll questions. Feel free to post.