I gave group 2. So my views :
You have not considered the length of Paper 5 : Advanced Management Accounting.All questions were from Practice Manual but majority of students failed to attempt even 75 marks.So the deciding factor is no. of questions attempted not the fact that questions came from Practice Manual.
No matter how easy the paper was, No matter all questions were from Practice manual, Mean marks range from 40-50 in Paper 6 :ISCA. Only about 5 % students get above 50 marks. Those who will clear with normal marks like 220-230 out of 400, get lowest marks in ISCA only.The valuation is hard to predict. Again, the fact that all questions were from Practice Manual is irrelevant.
You have also not considered the Shock value of Unexpected Questions of Direct Tax Laws : Questions on House Property, Salaries, 33AB.
You have not considered the unexpected Paper Pattern of Indirect Tax Laws : All case laws from 2-3 yrs back compilation.No latest case laws. There were many new unexpected topics covered in the paper.
Above things can only be felt if one attempts all papers in actual simulation mode.
So, i think that the pass percentage of Group 2 will not cross 10% mark.