I think most engineers work on the principle that things should get better over time, so may set an initial high oil pressure, that will become good at 200 hours.
The other way is to set the correct pressure, then as the engine runs-in, increase the now low oil pressure. However it is easier to remove a shim, than to find a shim in the parts bin, to add one shim. It seems as if that C150 now has tight running clearances, I wonder if the correct non-detergent oil was used during the run-in period...?
Those types of oil pumps are capable of very high pressures, and are used for hydraulic ram applications where the pressures are in the thousands of PSI. It is only the pressure relief valve that limits any destructive high pressures, which could result in a drive failure to the oil pump.
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