WHAT A MANIPULATION IN CA FINAL RESULT OF EXAM NOV,2015 !!!!!!!

Well, for your 1st question..
the % is with respect to the number passed from a region out of the total India. It is quite possible that very few appeared from the Eastern region and therefore the number of students who cleared is low. It is not, mind you, the pass % of students who have written from the East but a % of East vis-a-vis India.
For your 2nd question..
When a person clears both groups, it automatically means (s)he has cleared group 1 & group 2. So add the number (2440) of students who have passed in both groups to individual group total and you will see that the is no difference between the two releases. The overall difference of 4880 is nothing but twice the figure of students who have cleared both groups. Since it is added in individual group result, when shown separately again, it shows a difference.
Btw, your figures for individual groups are the other way around according to ICAI release. 

Group 1:     7324 + 2440 = 9764
Group 2:     6644 + 2440 = 9084

Actually the percentage comparison should be "number of students passed from a region (divided by) number of students appeared from that region". Your percentage comparison is "number of students passed from a region (divided by) number of students passed from all regions". Thats completely baseless. If more students wrote from a particular region, chances are more that there will be higher pass peecentage from that region. And that's why overseas has least percentage. Hope you understand what i meant. If you can get the number of students who appeared from each region and do a percentage comparison as mentioned by me in first para, that would be a more accurate comparison.