A CBSE letter led to the JEE percentile calculation goof-up

A letter sent by Central Board of Secondary Education (CBSE) to the school boards is found to have led the JEE percentile calculation goof-up as that carried contradictory instructions and formula.
The letter sent to the Punjab School Education Board by CBSE chairman, Vineet Joshi on 17 June, states clearly that admission to IITs will be "based on category wise all-India rank in JEE (Advanced), subject to the condition that such candidates are in the top 20 percentile of successful candidates in Class XII examination conducted by their boards in applicable categories." But a goof up hit as the formula mentioned in that letter for calculating the percentile was based on the total number of students appeared in the exam, and not on the total number of candidates passed in the exam.
The formula was also supported by an example that shows a calculation of percentile on the basis of the total number of candidates who appeared in the exam.
Using this formula, the Punjab School Education Board calculated the top 20 percentile candidates from around 3.3 lakh candidates who appeared in the exam, instead of the 2.2 lakh students who had actually passed, and come up with a list of over 67,000 students in general category only. Around 750 students from the Punjab board alone have qualified in the JEE (Advanced) 2013.
CBSE advisor B M Gupta admitted that the calculation of percentile on the basis of the total number of candidates appeared in the exam was correct.
But, Prof H C Gupta, organising chairman of JEE 2013, asserted that the top 20 percentile was supposed to be calculated on the basis of total number of students passed in the exam.