Higher constant flow or lower flow has no bearing on pressure on openers. That is controlled with the knobs by the pressure gauges. Flow changes at tractor only changes how fast pressure gets to the set point on pressure control valves. Maybe my drill has some of the cylinders leaking by or something but, if I don't lock lever in, my pressure on gauges vary during a pass across field. I have observed the pressure going higher and lower than the set point when I forget to lock lever in. Lock lever in and pressures stay where they are set. Just my experience with my drill, which could very well have a problem since it is a 1997 model.