I was going to pick this base up this weekend for my new king SleepEZ, but looking at the design I'm not sure I understand the layout of the adjustable slats.

 

The adjustable slats are just regular slats with a shorter slat attached to the bottom and 2 sliders that hold them together.

If I am understanding the design correctly, moving the sliders to the center takes the extra slat out of the equation and makes the slat the same tension as the non-adjustable ones.

Moving the sliders towards the ends progressively engages the short slat underneath and adds extra stiffness and less "give".

The adjustable "zones" appear to be positioned at the shoulder and hip area.

This doesn't make sense to me... why would one want to stiffen the shoulder and hip zones relative to the lumbar? Wouldn't you want more "give" in these areas?