When adjusting the bottom out on the dhx shocks (4,5,RC4), you are changing the air volume of the shock. Meaning that if you have the bottom out control fully out (counter clockwise) the air volume of the boost valve is at its maximum. When you dial in the bottom out control (clockwise) you are decreasing the physical air volume inside the boost valve (therefore giving the shock a higher or quicker rate of ramp up or non-linear quality). The proper way to adjust this control is to adjust the bottom out control to your desired setting, then adjust the air to the boost valve chamber. Reason being, if you fill your boost valve chamber with 150 psi and then adjust the bottom out control clockwise, you will actually increase the pressure inside the boost valve because the air volume is decreased from this adjustment. So if you know how much bottom out control you like with your shock, dial that in BEFORE adjusting pressure inside the boost valve. If you are curiuous about this, adjust your bottom out control fully clockwise, connect your shock pump to the boost valve and inflate to 150psi. With the shock pump still installed, fully unscrew the bottom out control fully counter clockwise. You will see that the pump will drop in pressure. Hope this helps.