Incident Workflow Notify Option - Not turning off email notification by project

Hi,

We are using the default Incident workflow, which has notifications turned on for Incident Assignment, etc.  We are using this for most projects, however some projects we do not want the email notifications.  I unchecked the Notify box on these projects in the Incident Workflow section, however email notifications are still being sent out for those projects.  Is that not the intended use of that flag?

Thanks