I'm sorry but I'm not inclined to look at a video. I have said before, it may be that the Z DRO is expecting 1000 pulses per MPG rev so each pulse would be one increment of say 5/1000 mm or 5 micron (assuming a 5mm pitch screw). But one turn of your MPG would feed it 1024 pulses to the Z axis so the Z axis would actually move 1024x5=5.12mm.