Are you worth $40k? or $120k?

It will depend entirely on experience and skills. Auditors get pretty steady pay increases for the first 8 years or so of their careers with the bigger private sector players, and the dept will take that into account when deciding salary.

From the page you linked it does look pretty clear that they’re recruiting for staff at 3 different levels. So I guess you’d get paid an amount based on your skills and experience as usual?