X-ray photon fluence from backscattering on lead

Dear FLUKA experts,
I am sorry to bother you again. I am facing an issue regarding the USRBIN card. I am studying two cases for the back scattering of the X-Rays (of energy 200 keV), one with the shielding and one without. For the former one I am getting this kind of 2d plot which I think is correct.

Whereas when I put the lead shielding (Lead) around the existing geometry I got the following:

I am not sure why both of the plot becomes different just by the addition of shielding. About USRTRACK, I just want to confirm that the spectrum from USRTRACK (Photon) shows the differential fluence of photons (primary plus secondary) within the target in other words the interaction of photons with the matter? On the other hand the USRTRACK (BEAMPART) shows the differential fluence wo only primary photons in the selected region, but in my simulations the USRTRACK with beampart is not showing any results.

Here are my files
wk1025-mgdraw.flair (6.5 KB)
wk1025-mgdraw.inp (3.9 KB)

I am sorry for loong message but I will be thankful to you for your guidance.

I had figured out rest of the things. Now I just need opinion that if the method to record the backscattered photons used in the input files is correct or not? And if I use mgdraw routine with BXDRAW subrogation to record the begging and final position, using Xtrack(0) amd Xtrack(1) respectively, energy etrack-am(jtrack), and direction of cosines then the output results will depict the ones for the scattered photons from the target?
I’ll be very thankful on your expert opinion.

mgdraw-1025.f (10.1 KB)
wk1025-mgdraw.flair (6.1 KB)
wk1025-mgdraw.inp (3.5 KB)