What ARE you talking about?
Do you think that M-M (or Superior) put less effort into workmanship or quality on ambulances than they did on hearses? The two were equally important. I've met M-M employees at the M-M meets in Piqua, and believe me, they didn't do any less on ambulances than they did on hearses. They all were quality built by skilled craftsmen/women. The designs were different, but the quality was certainly the same (top-notch), and they were proud of all of them.
Did ambulances get rougher treatment after they left the factory? Probably. Just the nature of the businesses. But they all were built to an excellent standard of craftsmanship.