Does this prove David Vizard's 128 lsa formula ?

It depends on what you are doing. A tight LSA will limit high(er) rpm or you have to use a bunch of duration.
There might be another issue here with DV way of picking cam, for him it's all about lsa and overlap and get the duration from those specs, a tighter lsa with same overlap would be less duration so probably lowering top end even more. Also he really don't give much info on how to pick overlap therefore duration, so it really ain't a cam formula just an lsa formula.