What does a so-called "third-party provision" (care agreement) entail as a (study) contribution?

Questioner

My ex and I included the following in the care agreement: 'The parties undertake to pay a (study) contribution to an adult child of 21 years or older as long as the child is engaged in vocational training or studying with reasonable results and in consultation with them, but no later than the time when the child reaches the age of 25. This stipulation for the benefit of each of the children of the parties is irrevocable, so that the children have the right to demand compliance with this stipulation if necessary. The signing of this covenant also applies as acceptance of this stipulation by the parties as legal representatives of their minor children.” Ex asks for continuation of current alimony; I do not know what a (study) contribution specifically entails and what I should pay. Can you provide clarity on this? (Child lives with mother, will soon be 21, studies at HBO and has part-time job(s)).

Lawyer

In this case it is a contribution to the costs of education, but if the child lives independently, that pushes the need up, income from part-time jobs pushes the need down. You can make an overview of the income and expenses together to determine what the child is lacking. I will give you a link with a link to duo https://www.nibud.nl/consumenten/studiekosten-bijdragen-als-ouder/