Chris Wilson commented on these a few years back
''Obviously the less oil is being lost past bearing clearances and through squirters and via oil pump wear on the rotors and housing, the higher the potential pressure. BUT given the flow of the stock pump is more than adequate to run the squirters AND allow as high an oil pressure as needed and more, (and *more* pressure is not usually any benefit), why lose the piston crown oil cooling? Seems someone thought "Let's CNC some cheap parts, sell them for a huge profit", *THEN* trying to think up a raison d'etre for them.''