ICAI exam system is very perfect.
Examiner evaluating (answer book valuation ) answer books Answer Key , scheme of valuation and mode of award of step mark will be provided to examiners.
Head examiner scrutinizing the correctness of valuation.
Checker confirming the valuation. Whether all answers were valued by examiner, duplication if any, extra/additional questions answered, counting of marks, totaling etc.
Copy/certified copy of answer books are available to students after paying prescribed fee so as to confirm the above Paper setter, Head paper setter, Examiner, Head Examiner, checker are independent persons.
Under this system no chance to differ the marks after verification