>>25501827
Here its based on the job. I think most jobs can be done in several ranks. So if you're an engineer, you could be from GS-6 to GS-8 (I'm making this up, I don't know the specifics) but then once you reach GS-8 you can't get promoted anymore until you take a different job like manager of the engineering department or something, which gives you GS-9 - GS-11.