Right.
I was messing around with the math add earlier but couldn't get it right, I think it's because I left the displacement parameter amount at 0.4

I'm guessing you can't really do it so it displaces on top of a displaced map. (It's not a biggie for me, I'll live lol)
Well, you probably can... but I think my eyes would probably start to glaze over, as I imagine it would be a rather complex setup. :)

Silke