Pump failure
There was a short period when OEM supplied technical information was interpreted that, like the S-70, a single pump failure would allow a pressure as mentioned in your obsolete reference. It was later learned after a North Sea operator experienced a pump failure that the pressure would indeed be "as low as" 5 psi. There is no missing psi as it never existed. The information was corrected in revision 1.4 and the latest revision to that document is 1.7.
It is also curious that the filter bowl studs were identified for replacement some time ago after an incident with the Australian operator of S-92's where a significant amount of MGB oil was lost thru a compromised filter assembly. None of this is secret. The MGB does continue to appear be an achillies heel of this otherwise incredible aircraft.