i'm no expert, but there are two things that look very interesting to me in the video.

The top of the skytec spring comes down about 1/2 inch when the starter is engaged, and eventually goes back to it's original position as the engine is running.  The ISKRA spring similarly comes down about 1/2 inch, but only goes part of the way back to its original position as the engine runs.  When the engine is shut off, the spring goes the rest of the way back to its original vertical position.

Looking at the end-on views, when the engine is shut off you can see the SkyTEC shaft doesn't move counter-clockwise as the engine stops.  But the ISKRA adapter shaft moves about 90 degrees counterclockwise.

Both of these tell me that the ISKRA really is causing friction between the spring and the shaft and keeping the whole thing wound up.  I had heard about this (and experienced it), but it's interesting to see the real-life evidence.   Unbelievable!

Mine wore out at 100 hours.