How can we compare in Employement Workflow flixfield current to proposed?

Summary

How can we compare in Employement Workflow flixfield current to proposed?

Content

Hello,

We would like to edit the 'Employment' approval flow, to disable the flow in case the
change in employment is a change in one of the descriptive flex field - DFF.
I would like to compare the worker CURRENT DFF filed value to the PROPOSED DFF field value for this.
I cant find the DFF (or any assignment DFF fields) under the proposed/current folder fields.
( i tried in the transaction console - > approvals and also from the BPM- > Administration - > configuration tasks ) .
How can i verify if a value of an assignment flex field has been changed in the current employment change?