You asked whether it's possible to do layer blending, and then commented that you wanna save on ND..
Isn't it implying to ask whether blending can substitute the use of ND, and this implies that the use of ND can potentially means reduced PP work, including layer blending?
Also, NM's reply mentioned about compromise between amount of PP work (blending) and cost of ND.
So it kinda imply that the 2 ( ND and blending ) could be substitute for one another, so I just wanna clarify how is it possible..