AWE conditional routing

We are planning to do the following using AWE:

1) Initiator/Submitter: Initates a transaction

2) Manager: First Approver

3) Senior Manager: Next step approver

4) Director: Next step approver provided "Review Required" (one of the fields on the page) is checked.

We wrote an application package in the criteria of the "Director" step which triggers and decides if the Director should be in the path of approval based on the value of "Review Required" .

Our requirement is that the Senior Manager can change the "Review Required" value.
Ideally, we want AWE to decide if it should be routed to the Director at the time of Senior Manager's approval.