Just come across this thread...
FWIW I suspect that RANS was talking abut the mag drop check carried out to check mag function, at TO or cruise revs, so that you know that the engine will run properly when you want it to, rather than the safety check to ensure that the mags are grounding properly when OFF, so that the engine stops when you want it to.
I've never actually done the safety check, which I thought was an engineering one. It's not that I'm against doing it, it's just that no-one ever told me too, when flying.
Again FWIW I always believed that BOTH - RIGHT, CHECK DROP - BOTH - LEFT, CHECK DROP - BOTH, CHECK NO DROP was the right way to do the function check, similar to the safety check.