Interesting idea, I mean time is merely a Human construct we use to define the process of moving from one state to another. It would be very interesting if the universe did have a tick rate which I'd guess would be 1/c but even then I'd be skeptical it exists at all. That said I'm open to the idea and the implications of it, as it would quantize any process to within a minimum time but I suppose that would disagree with quantum theory unless you could use a fixed tick rate to gain greater accuracy in the HUP but then as far as I can tell the HUP can't be broken so yeah I'd lean towards no tick rate but its an interesting idea and could maybe be used in other fields to see what could be developed.