Hi Ganesh
My first Key Figure "Sale Volume" is restricted by 0DAT(Current Cal Day), with offset range of -31 to -1. This gave me the previous 30 days results. I'm good here.
I created 2nd Key Figure exactly as 1st, and I have offset of -8 to -1.
3rd is CKF with exception aggregation - Average.
i'm getting values only for the last 7 days and not above. (as offset).
Please check attachment 
and advice,