According to the FRO, the maximum deduction is 50% of the employee’s net pay, which is calculated as gross pay minus statutory deductions and reimbursements for expenses (non-taxable).
The total deduction cannot exceed 50% of the net pay, no matter how much arrears there are in support payments; however, once the support payments + arrears is less than 50% of the net pay, the deduction must be moved to the lower number.
If the per diem or % increase is being used as an expense reimbursement because it is easier to manage that submitting receipts, that money is not taxable, and therefore should be exempt.
HR Insider staff