Using the Asobo Blender Addon, using MSFS PBR, I get the Base Color set 0.8 value by default. This is an error as we should have the value set to 1.0
Hello @rhumbaflappy,
This is a workaround where we set the value to 0.8.
If the value were 1.0, it wouldn’t be inserted into the glTF.
When you apply a texture to your object, it will override it.
Regards,
Boris
The texture does not override the 0.8 value. A trick we can use is adjusting the base color to add tint to the material. In the following, I use the 0.8 we are given, then a 1.0, then a brown tint added to the base color. These are accounted for in the gltf. In the case of the 1.0 value, the base color is not added to the text, as it defaults in the sim to 1.0.
I do note that without the Asobo addon, the sim uses 0.8 by default for it’s base color. Perhaps that’s the root of the problem. If it can’t be fixed, then the SDK should boldly explain that the Base Color needs to be adjusted, or your object’s color will be only at 80% value.
As a side note, the base color can be edited with a text editor, and the values set to 2.0 (for instance), and the sim happily shows a much brighter coloring. That cannot be done in Blender, as the values are clamped by the interface to 0.0 to 1.0
Looking at the python code, the fix appears easy.
Making those changes to msfs_material_props.py now defaults the Base Color to 1.0 when choosing a standard MSFS material. And the second change allows setting the values between 0.0 and 2.0, so we can lighten a dark material without using a paint program to alter the source.
Thank you for these suggestions.
They have been forwarded to the Blender plugin developer. 
Regards,
Boris