Regarding the flush proceedure....
With prior non-MB cars, I have flushed the power steering fluid as follows: 1.) Raise front of car to get both wheels off the ground; 2.) Remove, via suction, as much of the old fluid from the reservoir as possible; 3.) Remove fluid return line and direct towards a bucket to catch old fluid; 4.) Fill reservior with fresh fluid; 5.) With ignition on, but motor not running, turn the steering wheel from side to side (full stop to other side full stop); 5.)Keep filling reservoir and keep turning steering wheel until total system capacity has been replaced 1.5x.
The action of turning the steering wheel is what "pumps" or forces the old fluid out.
I have tried engine running method but the pump is so fast that you face the risk of running it dry. Also, it can be very messy with the high velocity fluid flow.
I find my version much more manageable and not nearly as frantic.
Is there someting about the MB design that makes my way not possible?