excel spreadsheet

I have a spreadsheet valuating recruits with several attributes.  My formaula totals attribute values.  I further use a formula to list a largest to smallest rating by using index(match(larger,nth)).  My problem is on duplicate ratings each recruit is listed sometimes, but not always.  The first set of duplicates it list each recruit with duplicate ratings, but the second set of duplicates it list one recruit twice and not the second one at all.  I have checked my formulas and they are correct.  What is causing excel to work and then not work?