There was a recent CAA publication (GASIL, possibly) in which they quoted the authority from another country - from memory, I think it was the New Zealand authority. The quote included the suggestion that the mags are switched briefly to Off, then back to both, in order to check they are not live after shut-down. However, in a side-bar, there was a note that the CAA do not agree with the New Zealand authorities, and that they think it better to go to each mag in turn then back to both.
Personally, I prefer each mag and then back to both, but that's probably only because that's the way I was taught. I don't know if going to Off would actually damage the engine - I'm guessing not, if the New Zealand authorities suggest it - but it certainly doesn't sound very pleasant when you do it. The only advantage of going to Off that I can think of is the small possibility that there is in internal fault in the switch itself which wouldn't be detected by checking each mag in turn.
I've searched briefly for the reference, but can't find it. Does anyone remember the article I'm thinking of, and where it was?
FFF
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