Sure. That's correct. But, you need to look at the job.
If you can get a job in lower Manhattan, you will get the maximum housing allowance. On the other hand, if you get a job in rural Arizona, the housing allowance will be near the low end.
There are only two jobs usually available in Manhattan (DIHS, and BOP). In rural Arizona (or Montana) there are usually more than two.
I've been in USPHS for 21 years. I can answer most questions you have.