Yes, it's hard to imagine how they plan on adjusting these hydraulic valves.
Actually I was surprised to see the indications in this series of posts regarding high oil consumption from these engines. In my '88 300E, I change oil about every 3,300 miles and never add between changes, in fact it's almost full when it's time to drain it.
When I bought the car at about 75K miles, I saw in the records a receipt for replacing the valve seals. However, there were several high dollar receipts from an independent garage that looked like bogus repair, rip-off if you will. This may have been one of them. The car now has about 168K miles and still zero oil consumption.
If the problem IS the valve seals, I would expect you to see a considerable amount of blue smoke when starting up cold.
'84 Euro 240D, 516K miles
'88 300E 5 Speed
Over 800,000 miles in