This is mostly based on discussion with Russ from DGS suspension and playing with Restackor. When playing with WP's, he has been pointing this out to me and I'm starting to see the light. I think that KTM has been using this feature a lot for bottoming control (both front and rear). It seems that if your bigger shims are really close to backer in faster oil flows (for example WP PDS 28 x .2 to 21 x .3 gap), it will really restrict the HS oil flow a lot. I have also noticed this same impact in front fork testing when altering just the back plate size in BV. And when then increasing the HS taper and keeping everything else the same, it will make the actual stack softer in HS damping to certain point. After getting enough distance it starts to stiffen again. This limit depends fully from stack setup and I have not really simulated these two examples. I'm not sure how much this can be really seen in dyno, since it will need a fast flow.