Welcome back to the Community, @Mellane.
You can edit the addition payroll item and mark the Track Expenses By Job. However, this will not add a class column to the payroll items listed under Other Payroll Items on a paycheck. Instead, in reports, these items are divided based on the division of the earnings items on the paycheck.
Here's how:
- In QuickBooks Desktop (QBDT), go to the Lists menu at the top to get to the Payroll Item List.
- Right-click the addition payroll item and pick Edit Payroll Item.
- In the Name used in paychecks and payroll reports section, select the Track Expenses By Job, then hit Next until Finish.
For more information about the process, consider checking out this article: Tracking payroll expenses by class, department, or location.
Just in case, I'll add this article for future reference: Set up and use class tracking in QuickBooks Desktop.
Please let me know if you have any other questions or concerns. I'm always here to answer them. Have a wonderful day!