The Dutch isn't great here. Uitvragen means to interrogate. It doesn't really fit the context for the client to have selected that word to use here. However, we translators often have to deal with clients who don't always use the language as they should. My hunch would be that the word was chosen to indicate an insistent demand of some kind. Something about which the client company is very strict. So the word stipulate comes to mind. You may have others who suggest similar terms which convey a precise and insistent demand.