Central Board Of Secondary Education [CBSE] — Low mark in class 12 CBSE board exam

I Nivedita of class 12, CBSE board student, was extremely disappointed with my 12th mark. My class 10 mark was 74%, class 11 mark was 84% and top 3 subject average in class 10 was 80.3%. I performed well in all term and model exams conducted in school. based on 30:30:40 CBSE Evaluation criteria, I expected a mark between 75-85%. I got only 69.6% in class 12 which was less than my performance in class 10 and class 11 mark. this is due to the CBSE's schools previous result criteria. I am the second batch student of that school. Since last year performance was low, we the students of this batch was suffering. why should I suffer because of poor performance of any other student. This is a fair injustice done on us. I know like me many students are suffering because of the performance based on previous batch. Please consider each student individual performance in 10th and 11th mark. kindly verify the marks allotted and concern of our future. Our admission and career has been threatened with the CBSE evaluation criteria. So please consider this matter urgently.
my school code: 55585