Well I think that’s correct. Are you sure you’re loading up the most recent version of that file and that you’re staring a new world?
I looked around and found this post: Creating classes that talks about creating new professions. Since you’re re-using an existing one it should be simpler and @RepeatPan lists the exact same file path that you’re using for the promote_to_profession command.
I’ve got some work to do but keep trying and let me know if you get it to work. If not, I’ll try to look closer at it later tonight. You may also consider updating your game to the latest unstable build and using the new profession/job API.