Yeah, Ok. So The issue is that it's common to open Photoshop and merge all those outputted sheets into one images using the RBGA channels. However, there is no standard; people put whatever mask in whatever channel and then when they import it into an engine, they use the silly nodes to define what's their roughness/metal/AO/etc.
Issue is that right now, Turbo doesn't have a node editor, and from the looks of it, Josh wants a standard which is non-existent within the art space. Really big mess right now.