A consultant does a lot of different things: write vacancies, screen candidates, take tests, draw up contracts, pay wages, etc. The consultant also receives a salary for this. At the same time, that consultant works from an office, which also generates costs, such as rent, electricity, coffee, the gadgets they hand out,... Someone has to pay for that. Fortunately, that someone is not the temporary worker.
Who does pay for the work of the consultant? That is the company that hires temporary workers. As a temporary worker, you receive your wages every week, and at the same time an invoice is sent to the company where you work. This will show your wage, some costs associated with your wage, but also a coefficient. That's a number by which your wages and all those other things are multiplied. This is how temporary employment agencies are paid for their work.
That coefficient can be different for each profile. The more difficult a profile is to find, the higher it will be. The opposite is also true. A temporary employment consultant will have to search longer for a highly specialized maintenance technician who has certain certificates than for a warehouse employee with no experience. That is why the coefficient is slightly higher with one profile than with the other.