I agree X2. Pressure relief affects max pressure not min. Either the two tests were done at significantly different oil temps or the oil was changed at the same time as the adjustment was made.
When the pressure is turned down to 70 at cold start what is it hot with the rpm up? I would consider 70 psi max and 20 psi idle pressure at normal oil temp to be acceptable.

Oil pressure is high cold because the oil is thick. No need for 20w50. Idle oil pressure number isn't a concern. I'd run 5w30 or 40. I run the same pump in my drag car. The relief spring has 1 1/2 coils cut off. 30psi@idle, 70psi@7000. Since oil temp seldom gets to 175 degrees it runs 5w25. 4.50" stroke run to 7300.
Doug