Child Benefit deduction query

Hi - I need some advice regarding the child benefit calculation I have just completed my self assessment for last year (2021-22). I earn between 50-60k so I have to pay back some child benefit. So far so good But I just received a new tax code following my self assessment. According to this notification the new code is based on my Child Benefit deduction now being £4476. I have no idea what this means, or where that figure has come from. The total Child Benefit for the year (2 children) is £1870. So how can the deduction be so much higher than this? I don't understand what this line means, or why it can be more than 100% of the benefit I receive thanks for any help or explanation

Hi
A deduction of 4476 in your code would result in you paying back 40% of that figure.
If we only put 1870 as a deduction you would only pay back 40% of that figure.
Thankyou.
Regards.