The amount of tax is not adjusted retrospectively, so make sure that the fund has your current tax card in advance of paying the benefits.
The tax is always determined by the date of payment of the benefit, regardless of the period for which the benefit is paid.
Example: The benefit is paid simultaneously for January and February, so that the payment date is 10.3. The tax of the entire benefit payable is determined on the information of the tax card that is valid on March 10.
The fund normally receives automatically the tax card that is valid from 1.2. onward. This tax card is always written for salary, so its information will need to be converted when taxing benefits. Read more about the tax card for salary below.