Analogue systems

Hello all. I'm new around here (and having a bit of a struggle with 
this whole user group thingy, so apologies for any repeat posts 
and any other inexplicable goings on), so thought I'd say hi and 
Happy New Year to one and all. And with the formalities out of 
the way...

I see that AS have a unit available incorporating two RS200's, 
designed for the RS8500. It's not immediately obvious to me 
what advantages twin RS200's would bring, (other than having 
16 steps instead of 8) and I wonder if anyone would be able to 
explain what additional possibilities this would open up.

Cheers