Its a weird system, my advice would be to look at your own kid and dont let scores affect your opinions and also talk to the teacher.
your child's teacher can explain the specific outcomes. Also in relation to the other subjects.
Cito grading is not based on number of correct answers, but rather on score relative to other children who made the same test. For example 43 correct is a V this year, but could have been a III in a previous year.