Viewing completed sub tasks

Hi all,

Newbie to Omnifocus, and I’m pulling my hair out trying to work this one out.

My workflow has lots of tasks (projects) that might require 3-5 subtasks.
What I would like to see in the project (or custom) perspective, is the completed sub tasks so I know what has been completed so far. The problem I am having is that it seems that the only way I can do this is by enabling “view completed” in the projects view, but by doing so I see all previously completed projects.

Can anyone suggest if/how this could be done?