If you work in a high-technology field, as federal employee, you are often underpaid in comparison to the private sector. I'm a contractor and I make 1/3 less than I did when I was still in the military.
I've found that agencies often lie with regard to rates and get away with it because of their leverage due to the panels. If you check the governments mandatory reporting regarding contracts (often very hard to search) you might find they're paying far more for you than for military staff, regardless of what you're receiving.