Where did Skill 12 = professional come from?

[roguebfl]

Originally Posted by nik1979

So am I to assume that this value was arbitrary for game purposes?

I think I remember reading about 12 as the professional skill level in 3e also. Most of the old job tables entries function on the 12 level.

as a follow up question:
Are Job Rolls in B516 considered routine? I remember in 3e they were not, but has that changed in 4e?

it not arbitrary, and unless the job is 'adventuring level stress' then it's routine.