I had plumber install backflow preventer outside and when water pressure was measured it was 85. He suggested putting in a pressure reducer inside after where water line splits for sprinkler system. Reduce can be adjusted to 25-75 psi. Was this a mistake? should I have stayed with 85 and pressure drop would come down when got to heads? Since I'm putting in many feet of drip, I assumed that a pressure reducer was a good idea. I shaving this large one in-line better than the smaller ones at the zones?