The repayment of the employee’s NI needs to be done of their old NI Category, as it is not possible to put an Employee Amount against NI Category C
It is therefore suggested you use the following process:
- Leave the employee on the old NI Category (Note: probably A).
- Calculate the changes required to the employee’s and employers NI.
- Enter the changes into HR Record > Payroll Functions > Tax and NI Override.
- The employee’s NI this month will then make those changes to the old category.
- After period end, change the NI Category to Category C.