This is an interesting tread ...............

For years, Mercedes Benz has provided avenues for adjusting timing.

I have a 1959 300SL, and a 190SL (Same Year). Both cars have a little dial on the dash board, which is used for retarding/advancing timing depending on fuel octane (Pretty advanced for vehicles built 45 years ago.) My experience with this little dial? It does work as intended.

Point being, why would Mercedes provided a means to adjust timing, if it were no use?, and why would they provide this for so many years?