Oil pressure question

I just had a 2015 Sea Ray 510 surveyed. Boat has Cummins 550's with 350hrs. The oil pressure on one engine was 16 psi lower. At wide open port was 58 psi and starboard was 42psi. Anyone with these motors have this issue?

What did your engine surveyor think?
I always have a difference of between 4-8psi depending on conditions.
It was explained to me that because one engine has the oil filter mounted on the opposite side of the engine, the oil has further to travel, hence the difference. It could be total BS, will let others opine.

Not sure about diesel but I know on Gas engines you need a min of 10lbs per 1,000 RPM.... Before Bang!!

Could be any of a number of things. Simple defective sending unit ( not necessarily the one that reads low). An overlooked oil filter partially plugged ( maybe the hard one to get to). It is possible oil level is low. On worst end of list, maybe somebody has doctored one engine to bring pressure up ( ie adding a thickener). You say you are in survey stage, ask for maintenance records, send oil samples out, have a professional cummings mechanic (marine of course) look at it. Few dollars spent now might save several thousand's of dollars later.