I'm trying to add edge loops to define corners on a subdivided model. I want to view the subdivided result while working on the original mesh.

As I understand it the following should work:

box1Node—->—-subdivideNode

If I display the subdivideNode but select the box1Node then when using the Edge Loop tool from the shelf new nodes will be inserted between the two original nodes.
Except it's not working, the new nodes branch off from the box1Node so I don't see the result and have to reconnect the subdivideNode. However, if I use the PolySplit tool (which I think is essentially the same node) the node is added correctly.
Am I missing something?