very first in cross table attribute only produce exact result?

[vignesvar]

Hi all,
I created a report using drill down concept in cognos 10.2. Here row level as name, group, work these are drill behavior attribute. Performed summation   name and group.
when I drill down name I got exact result both name and group are same. When I first drill down group It shows different result that mean as usual correct result what is overall and group wise. 
My question is We get exact result only what is very first in cross table ?

Please let me answer.
Thank you guys,

Have a nice day.