Promotion Approval Rule - how to check job level increase out of sequence

Summary

promotion where job level jumps by more than 1

Content

Wondering if it is possible in the Approval Rules interface to check if a promotion jumps by more than 1 job level? Or is this achievable with BPM?

The logic that I would like to implement is something like:

Worker New Job Level > Worker Current Job Level + 1

I've looked a bit, but math operations don't seem possible in the Approval Rules interface.