Thanks for Greg's comments. My hammer has 1 lbs weight. Lots of people use 3 lbs hammer in this area, but this small one works.
Just wanted to tell what I got. For the test mentioned above, the reciprocity was so bad and not consistent at all. I moved the test points from "the bad spot" to more rigid spot, and it gave me very good results. No issue any more.
I am thinking "the bad spot". Those area are filled with epoxy material and not consistent at all. I guess the reason might be not only the high damping but also the non-consistent filling or say non-linear problem.
Again, thanks Greg