Not quite, the ride height adjuster doesn't alter the length of the spring, there's no preload applied. The adjustment is there to ensure there is no preload on either main or rebound spring. The available suspension travel should always work out to be the same, and the rising rate stops bottoming out.
I confess to being a bit of an evangelist about this mod, it has made a major improvement to my car, as far as I can see there is only one downside, the cost.
