Paul Clawson found an interesting bug in fsdsxtweak.exe – when tweaking VC materials which follow a particular naming pattern (e.g. $vcpanel1, $vcpanel2, $vcpanel3), you will have the tweak of the material wiith the shortest texture name applied to all those materials (due to the way I was using substring matches in the code).
You can get a fix for this issue here fsdsxtweak.exe v2.81 download. This patch should be applied only over version 2.8. If you have not hit this particular bug, there is no need to upgrade. Installation is simple – go to your FSDS folder, and overwrite the fsdsxtweak.exe file there with the one in this zip file.