That’s exactly what I was trying to get at too. Depending on the GPM, the meter will determine total flow. If the pressure is still 65psi, there will still be misting without head regulation and more flow per zone.
Do I understand correctly, you didn’t regulate the heads?
The MPs are more efficient with regulation. The nozzles themselves have no regulation and will turn faster than normal without it, wearing the gears. Plus, if the heads are regulated it will help when running zones together.