Also, they don't know the correct dynamic ride height of your bike when they publish the guides.
Your bike may be designed to run at a specific head angle which you won't find by setting the fork at the set pressures printed on the fork leg.
Basic guides are 25% for 100mm and below, and 33% for up to 200mm. My 150mm bike rides best at 40%, and my 120mm HT rides best at 30% sag for my riding style.
If I'd gone by the recommended settings, I'd still be struggling with arm pump at Afan.
I altered my settings to suit the environment that I rode my bikes in most.
If I take a trip, set my bike up to suit the area I'm riding in.
Those guides were written by some guy in an office IMO, because they clearly weren't written by anyone that had ever ridden RS forks on a trail. Because they ride on the spring, and the rate is so progresive to offset the lack of high speed compression damping, you need to run a lower spring rate to achieve any smal bump response.