The block diagram shows that the line out goes through an AD/DA cycle. You would think that it would be a cost savings to them if they made the line out come directly from the pres before they AD stage. It also looks like the Digi out is a summation of all 4 channels.
It looks interesting. I will be staying tuned to see how this all pans out. For the time being, i'm pretty happy with my busman most FR2-LE