Kyomu is right about this. my first few shows i never had a bodyfat test done. i had been competing 10 years before the first b/f test i ever had. i went into those shows shredded. later on, i had access to b/f testing, and they would show 3-4 percent before a show. you tend to not diet as hard if you think you are 3-4 percent, because that's what everyone competes at.
i was never as lean on stage once i started getting b/f testing done, because they always showed i was lean enough. and i would relax and eat more icecream. if i never got tested and just felt my low back, i would have kept getting shredded.