Shear Stress Verification Problem

I am studying the granular flow on inclined plane with different angels. In my simulation, x is flow direction and z is perpendicular to the plane. On achieving the steady state, profile for velocity, volume fraction, shear rate, shear stress and pressure seems fine. But when profile for shear stress in direction perpendicular to the plane (in my case it is zz) and shear stress in xz direction are not in accordance with the profile obtained from the momentum balance equation.

As I am still trying to figure out why is this happening? Can anyone suggest to make it right?

I used the compute stress/atom ke pair to calculate the stress and as it does not include the contribution from the average fluctuation velocity, so I write the code to include that as well. Even then result are not satisfactory.
Here I am attaching the simulation file(in .txt format) and images for kinetic energy, shear stress in xz and zz direction.

All quantities are normalized according to the 'Physical Review E 81,041307 (2010)' .

Regards
Puneet