So it sounds that the percentile might change after Feb scores. Am I right?
I do not think so. The scores from Jan and Feb 2013 will be used to do statistics for next two years (2014 and 2015).
Your son's percentage is based on the last two years scores (2011 and 2012). And current year is 2013.
Percentage for year 2013 is calculated based on the score data from 2011 and 2012.
Percentage for year 2014 is calculated based on the score data from 2012 and 2013.
Percentage for year 2015 is calculated based on the score data from 2013 and 2014.
