You have to understand how many people come on here stating they are a certain BF% and then you see a picture and wonder where in the hell they came up with the number. There was a dude not too long ago that got tested hydrostatically and said he had 3 tests all showing him just over 5%. He still had a bit of a gut, not a line of separation in his quads and was smooth as a baby's ass. Probably 13-15%. And I dont think he was lying about the results either I just think many testing methods are flawed. So yes, when you said you were 6.3% and 16 weeks out I am going to want confirmation with a pic. I am not doubting for one minute you were calipered and that was the number they came up with.
As far as testing methods go I prefer calipers and here is why. If you do a 9 site and have an experienced person do them you can get accurate and more importantly consistent results. You can do them more often to chart progress. Most importantly from a bodybuilding perspective we are most concerned with sub-q fat which is the basis of all caliper readings. This gauges the look we are after. Bod-Pods and Hydros can be more accurate but can also be widely inconsistent due to needing to be properly calibrated and a bit more air in your lungs or even having a bit of stomach distention can radically change your readings in the Bod-Pod.