I think in a sense Clanad you may be falling prey to the same error as Plivey.
If time is quantised around the plank time then to talk about time smaller than that (even to say all bets are off) is as meaningless as talking about before the big bang - but maybe you're aware of that, I can't really tell from your answer.
I'd also be a little more circumspect about saying that the multivers theory can
never be tested. It's certainly very challenging and beyond us now but I don't think Einstein ever thought the EPR paradox could be tested and Rutherford certainly thought nobody could get usable atomic power.
Don't get me wrong I'm not talking about moving anything as large as a human between possible universes or actual people travelling in time - but imagine if we could create micro-black holes - far beyond us now but not inconceivable.
Such objects could offer just the tools to probe how space and time are actually put together.
If anybodys interested in time travel there is an online lecture here:
http://vega.org.uk/video/programme/61 by Professor Paul Davies who's a real expert on the subject. The vast majority of it is pretty accessible with very little mathematics.