System Information
Solus Project (Linux 4.8.7)
NVIDIA Binary Driver 370.28
NVIDIA GeForce GTX 960 2048 MB

Blender Version
2.7.8a

Short description of error

When setting a custom scale in the FBX export dialog, the scale is seemingly applied twice, once at the FBX global level, and once at the object data level (via global_matrix, I think). I work in centimeters (0.01 scene unit scale) and at a 10:1 scale on top of that when doing FPS props, rescaling on export.

With the current FBX export code, a scale of 0.5 in the FBX export dialog is applied twice, leading a 2m (200 U) cube to be exported as a 0.5m (50 U) cube.

Replacing line 2676 of export_fbx_bin.py:

scale_factor = scene_data.settings.global_scale / units_blender_to_fbx_factor(scene)

With:

scale_factor = 1.0

Does result in the correct scaling, though I have not tested it for any other Blender Unit scaling.
I have tested the generated mesh with another program (UE4), and got the same result, which rules out the importer as the source of the bug.

Exact steps for others to reproduce the error
Open the attached blender file, FBX export the 2m cube at 0.5 scale. Import the generated FBX file, will result in a 0.5m cube, rather than 1.0m cube.