Yup, especially if you're an IP coming off AD you could become an ART, get GS-13 and an increased step with a superior quals package and then have a 25% 3R on top of it.
By the way, does CBP get the same SSR that ARTs get?
Edit: SSR 0558 for GS-2181s is for Element : Department of the AF. More coin being lost out on.
https://apps.opm.gov/specialrates/2014/table055801012014.aspx