workflow - how to prevent the author from editing their own content?

Hi,
I am using the workflow module in one of the projects and I have basically 6 workflow states. In the workflow settings I have set it like this - the author will only be able to view the content beyond a workflow state. However, while testing it, I am able to find that the author is able to edit the content beyond the workflow state. I am guessing that we need to override the role permissions with workflow permissions. How can it be done?

Am I missing something here? If so, kindly let me know as to what else might need to be done.

Thanks!

Mahi