Bypassing Check Escalations for active workflows

I am looking to implement Check Escalations in my org, but I do not want to affect any active workflow. I would only like new change processes created moving forward to follow the new escalation process. Does anyone know the specific criteria 'Check Escalations' is using? Is this possible?

I've tried clearing out the 'escalated_to' and 'expected_duration' properties on the active activity on active workflows prior to running 'Check Escalations' method, but the activity assignments are still escalated. 

Or if there is a better practice for managing existing workflows when trying to implement a check escalations process, I would appreciate the feedback.

Thanks,

Paul Sheehy