Well the document I have in-front of me states for KA "Captains, grade 4 & 5 ground staff (11B)", CX FO/JFO/FO/SFO get economy. That is not based on DOJ, but rank.
You're confusing eligible travel class with boarding priority. When flights are full (more staff than seats) it goes to DOJ only, within the same priority. Been like this for over a year. We no longer get to use eligibility for a cabin that others aren't as a way to get on. *sigh*