Use Project Header DFF to drive approval routing

Using Grants and Project modules, where the goal is to allow a project administrator to have limited control over approval workflow for project related requisitions based on a project header level DFF. For example, an approval rule may be defined that says if DFF value is "high," then use a dollar limit of $1,000; while if the DFF value is "normal," use a dollar limit of $5,000.

The DFF available in requisition approval workflow appear to be Cost DFF, not project definition DFF.

Is there a way to push the DFF value from the Project Definition into the Cost DFF field, or are there other suggestions for achieving something like this? Project Administrators will not have access to the requisition approval rules workspace.