My oil pressure sender is in the rear main bearing inspection port. Since going to dual HPOP, my oil pressures have been running lower. Cold idle can be in the high 40s, low 50s. However hot idle runs 17-19 psi. This is about 10-15 psi lower than when I had a single HPOP. Plan to put a Melling LPOP in the future engine. I do not completely understand why the extra oil in the HPOP should have this effect. I do not think it is loss of oil viscosity but the first oil analyses should be in tomorrow.