Substance Importer bypass sRGB

After doing some A/B testing comparing the maps contained inside an SBSAR imported using Unity's Substance support against the same maps exported manually from Designer, it seems that Unity considers all inputs to use sRGB sampling. When I disable sRGB sampling on a manually imported texture (say, height) and swap it in, the effect is different.

It seems to me that height, ambient occlusion, and metallic/roughness maps should use linear sampling, right? I couldn't find a way to set that property on the textures returned from the ProceduralMaterial instance they are wrapped in (I think it has to be done through the Texture2D constructor) and it doesn't seem to be something you can configure on the material instance itself.

Is there a way of changing this in script on import that I'm missing? If not, would it be possible for UT to expose a parameter to allow linear sampling for the data channels in Substance materials?

Thanks,
Adrian