Good advice! Not having worked on that many MB's, I assume that the reason is the cam shaft drive sytem and the belt/chain tensioning. Turning in the wrong direction can unload the tensioning and cause the system to jump a tooth! Then you have real problems. It also helps to remove your plugs so you are not fighting compression. Larry or others, please correct me if I am wrong!
Also, lets not forget safety. I hear of people getting hurt and killed by cars falling or rolling on them during maintnence. I know of two personally (both professionals) that narrowly escaped death! Here are the rules: Always set the parking brake, always have an educated assitant in the immediate area with the knowledge and tools (jacks) to extricate you from a vehicle that slips off jacks, chock the wheels, use quality ramps and jackstands on solid flat ground (not dirt). These are simple, cheap, and effective!!!!!
One more question for the members - I have a 300TDT, what is the best way to rotate this engine to gain access to the torque converter drain?