Timing does indeed mean the cycle of retracting the nozzle to allow the bb into the hop unit, then allowing it forward to seat the BB into the hop before the piston comes forward. If you're not getting a feeding issue that should be OK but if the nozzle isn't actually seating on the feed lips of the hop rubber properly you may be getting an air leak.
The chamfered tip of the nozzle should seal into the end of the hop rubber (the feed lip if you will). An easy test is to reassemble the gun, turn it upside down and place a small piece of paper over the feed tube. When you fire the gun the paper should move only minimally, if it blows off then there is air escaping down the feed tube.
Also - it may be the camera angle but your barrel doen't look straight in your hop unit - it may need twisting slightly to line it up.