Tax Free amount and Untaxed Interest Amount

Hi. When I check "How your tax free amount is calculated" is the amount for untaxed interest on savings and investments the final figure or is it updated each time HMRC get a report from a bank?

Hi,
The untaxed interest figure in your tax code is a prediction based on the previous year's figure, and may not update if a bank or building society informs us of a different amount received in the previous year.
If you would like to check and update the figure present in your current-year code, contact us by webchat or phone via Income Tax: general enquiries
Thank you.