Steve, I think you are assuming something that may not be true.... I believe that the dial indicator measures things in addition to the chain elongation.. therefor is the proper way to see if your valves are acting at the proper time in relation to the crank....
It puts ALL the criteria which are necessary to get the valves open at the right time under Cumulative Test.... which the cam mark/crank mark check does not.
Anyway, the Mercedes Benz Factory Shop Manual says to use the dial indicator test if ANY PERFORMANCE Complaint is extant.