Visvesvaraya Technological University — Revaluation

My son rohit is a student of pesit, bsc, banglore.His usn no is 1pe15ec123.
His sgpa in 1st semester was 7.75. Result showed that he scored less marks in maths than expected (Grade c).
Accordingly he went in for revaluation.
Surprisingly his grade after reval has become f. How can someone who was above average be failed in reval. It is unlikely that in a subject like maths which is very objective, someone can slide down so low.
Thing requires immediate reconciliation as future of child is at stake.