Item Change Order approvals in BPM based on Item DFF

We have a requirement from business to write item change order approvals in BPM.

If DFF value is OSP, send the approval to A and B.

If DFF value is SPO, send the approval to B and C

I have written the rules as above and approvals are not working. Instead I have used item.primaryUOMvalue and it works.

Please let me know that we can write the change order approvals based on DFF value.

Thanks,

Praneeth.