Let's consider a situation. If the person whose ranked first is on 90 raw mark (RM) and you come second with (case 1 -) 89 and (case 2 -) 80. And the rest of the class gets 70.
Then in the Exam, the top person gets 90 and the second person gets 85. And the rest get 50 (assumin' they all have a bad day).
Then in case 1, the Assessment mark for the person ranked 2nd would be around 87-88. Whereas for case 2, the mark would be around mid-70s.