It's the exact same thing though. Doesn't matter if the screw rotates or the tube rotates, it gives the exact same result.  It's not surprising at all. It's just common sense. In practical application though it is better to turn the screw instead of the tube. Less exposed moving parts so it's safer and less maintenance.  Not sure why you or anybody else would be surprised by this to begin with honestly.....,(reply>), Did you?