For whatever reason, I can never mange to get the advertised render passes:
Diffuse + Indirect + Specular + Reflection + Refraction + Incandescent + Scatter
to equal the Beauty.

Yes, I've got linear workflow, 32-bit HDR export format (openEXR doesn't seem to play nice with photoshop?). It ends up completely blown out. I suspect it has something to do with the mia_material_x_passes material I am using. The diffuse pass had the object (a poly plane) with the mia_mat completely white. Why would that be? But even so, the other objects with simple blinns end up overexposed after all the linear dodging (add).

I generally give up with the whole render pass approach, it seems more trouble than it's worth.