As thresholds and rates changed part way through the tax year, this may be why there is an adjustment in the final payment.
Without any of your figures and more details, we are unable to advise if your calculations are correct or not and what may be causing the isssue.
Please see the following rates and thresholds and when they changed:-
Rates and thresholds for employers 2022 to 2023
Please call the Employer Helpline 0300 200 3200 to discuss further if required.
Employers: general enquiries