The values given in the table are recommendations from the manufacturer. Your HP regulator should not exceed an outlet pressure of 850 PSI (expect older markers like AutoMags). Higher pressures increase the wear of affected marker components, they change the performance and can even cause damage to the marker.
A change in the working pressure of your HP system will result in altered muzzle velocities. Therefore the muzzle velocity of your marker has to be measured and adjusted after every change!