I joked that my interview was a lot shorter than that of most of my colleagues (some of theirs ran 2 hours, I think I was in and out in under 15 minutes) because the feds had good files on me going back to my college days and they were just going through the motions. Or perhaps I just have a dull life.
Same thing here. Have copies of my SF86s going back to my initial investigation when I enlisted in the Marine Corps. Last one was basically a short telephone interview followed by a drop in visit by the contract investigator. Ten-fifteen minutes total?