Extruder Tuning CR-10S HELP

Ok so I've read up on calibrating my extruder. So I did the test with the hotend on and plastic coming out of the nozzle. It only extruded 86mm. I tried it a few times with pretty much exactly the same length. I then tried it without it going through the bowden tube and NOT extruding. With NO resistance the extruder moved exactly 100mm of filament, the amount I told it to move.

So what do I do now? I've see two different tutorials one that says extrude some plastic through the nozzle and measure and one that says let it go free and not into the hotend.

Which method is correct?