I'm a new owner of a '95 E320 so I haven't noticed oil leaks relating to oil level.
I just think it's strange that oil level could somehow affect oil pressure, 'specially 1/2 qt.
My 320 does have oil pressure *almost* pegged and idle, but so did my '87 300TD.
I can see how a higher oil level might affect areas that are subject to oil splash, but how does it make the head gasket leak?
There are cases of Benz (and certainly other makers) offering a red herring as to the cause or correction of a fault. It gets the service writer or shop foreman off the hook, if nothing else.