Dont forget even though stocks antenna but with additional windsurfer that is able to focus and improve the signal
I notice that there were significant differences in each video: the altitude, weather, location and app used. It's great information, but it would have been ideal if everything else that affects distance had been kept the same.
Also, you see from the last video that he has the omnidirectional antenna for the control signal and the directional panels for the video/telemetry (which are angled at 45° for some reason). My ArgTEK kit has three omnidirectional and three directional antennas. I'd assumed that the directional panels would be better for distance, but maybe that's not the case. I'd also assumed the directional panels had to be pointing straight up or down (parallel to the omnidirectional control antenna), but maybe that's not the case either.
Anyway, all the videos show that the Magic Power mod significantly improves the video/telemetry range, so thanks again to PapaTita!