what is the cost of r12 these days?
and the cost of the new stuff?
i think it may be a considerable differential.
so, if you have an older benz that develops a/c problems that result in a continuing loss of r12, it might pay to revise the system to use the new stuff.
i have made that conversion for my 1986 560sel[250,000miles] and my 1987 560sec[80,000miles].
i can detect no deterioration in cooling capability. and the cars operate in the environs of the texas gulf coast, a tough test.
just some thoughts.