The screening process is there to protect the student. DAEFA like most academies, try to ensure that only students who have a reasonable chance of passing the course, part with their money!
Why would one trust the school on this screening? The purpose of the academy is to train students against money, not to do job interviews. If it is like in Europe when students fails to have the required level the academy does not let them go through the exams, screened students or not, as bad students could compromise the FTO approval. The real screening is AFTER you pay the money, when the academy decides or not to let you attend the exams. These preliminary screenings (which also exists in Europe) seems more like BS to me. You basically pay for it and it makes you feel like you joined the NASA while you're just allowed to spend some money with them. The real thing is when you're authorized to proceed through the exams once you already paid the full course. Without such an approval from the school you cannot attend the exams, and the whole money is just gone.