Most damping adjustment are not linear, because most adjuster is control via a bleed valve.
If you imagine a garden hose:
If you open the tap a quarter turn when it is fully closed, you get a lot of water coming out
If the tap is already half open and you open another quarter turn, the change won't be as great.
It is the same with the adjuster, a "click" on the stiffer end makes a much bigger difference then a "click" in the softer end normally.
This is why sometime suspension have a lot of clicks.
Because if you want to cover your range from full stiff to full soft, but still have control of the stiffer end, then you need to have fine adjustment and lots of them.
Example, let say you have 30 clicks that that move the valve 0.1mm per click.
If you want want to half it to 15 clicks, you have one of two choices.
1. change the pitch to 0.2mm, so you cover the same range in 15 clicks.
But you lose the "fine" adjustment you need at the stiff end.
2. change the range so you only have 15 clicks adjustment at 0.1mm pitch.
But you lose the soft end of the adjustment and that could mean even the softest setting still ride too harsh.
When it comes to damping adjustment, you want to make sure that you have the range as well as the fine adjustment you need.
The second thing is to make sure that you have the right damping force.
I see some damper that are WAY over dampened, and that mean on full stiff the damper stop the suspension from moving in it's natural frequency and can lead to all kind of poor vehicle dynamics that you just do not want in a car.
Hope that helps.
Jerrick