Unresolved Filament issue or printer issue?

If it is only 1% out when you do the extrusion calibration test then I wouldn't worry about it.
Part of the video is confirming what your extruder is actually doing and for a 1% difference I wouldn't adjust the eSteps for a 1% error.
Make sure you are doing the calculations correctly because... it is important and most folks are a lot more than 1% out of tolerance.

 

But Oisin is doing this based on an extruder that is more than 1% off, it's just coincidence that his extrusion multiplier is within 1%. That has been my point all along.

Look at it like this. If you had a car that had very advanced timing and pings badly with regular gasoline, you don't FIX it by buying premium gas instead, no matter how good it might run then. You fix the timing first then look at all the other stuff. Now do you see my point.

 

Make sure you extrude at the same temperature each and every time. It really only matters that your extruder pushes 100 mm of filament into the hotend. Also, since we are using 1.75 mm filament, what no one ever tells you is that you need to have a lot of pressure pushing the filament into the hobbed bolt, so screw in the idler arm screws as far in as you can, maybe even adding a few M4 washers on each side. 3.00 mm filament requires a lot less pressure to extrude than 1.75 mm. If there is any slippage you might not notice it in the print as it could happen during infill but it will eventually rear it's ugly head when you are doing your most important print.