I have done BF testing several times using different technologies. The lowest number I ever obtained was with under water testing at age 30 that was 5.5%. I thought at the time that the test result was low but hey I felt great at the time and I was in great shape - cycling, running and strength training.
About 5 years ago, I had a trainer at Equinox use the skin fold calipers. He takes 3 readings and adds them together and then goes to a chart that has age groups. He comes up with 16% based upon my age. I said...wait a minute, I was expecting 8-10%. If he used the age column for 30 years old, I would be at 10%. Supposedly, the age correction is for visceral fat which is fat that accumulates around organs and etc.
My waist has not changed in 40 years and if anything is slightly smaller so where is this visceral fat accumulating or is my liver getting smaller? There is no answer to this question so a way to correct is by using an athletic discount. Many scales have an athletic setting to compensate for being an athlete.
In the end, the trainer says, you are in great shape, what BF do you want to be. IMO, BF testing is a blunt instrument. However, skin fold testing or observation in the mirror can tell a lot about ones shape and BF %. But much like how high one can box jump or deadlift or how low ones BF, they are metrics for consideration and indication of performance and strength. There are no time bonuses added at the end of the race for the racer with the lowest BF measurement.
What I have found to be true for me, even sprinting, is that the lower my weight the better my power numbers and sprint times. Of course, there is a point of no return.