Inheriting security from main process to subprocess.

I have a use case, where I need to Inherit the Parent Process Security(Initiator Level) to each Sub-Process, But the Inherit Option in Sub-Process Activity is not working as expected and in the assignment tab, When I select the "Run as Whoever designed the Process Model" it is working fine,which is strongly discouraged by our practices.
Please let me know how exactly the Sub-Process Security & inherit option in sub-process activity node works (or) do I need to configure security explicitly for each sub process.?

OriginalPostID-229864