Hello again Colin,
I had that slightly wrong actually, because I also heard of this danger relating to dragon and tiger chi gung, so not necessarily outer dissolving.
But generally I get the impression that it certainly is a pre-requisite. I am thinking of the clearest example set out in the diagrams in “Relaxing Into Your Being”, pages 34-36, about preparatory, intermediate and advanced practices.
Other than that, though, I find this theme running through the whole of this subject; preparing the body sufficiently through stabilizing the downward flow of energy; the analogy of ensuring ample insulation around electrical wires to ensure they can handle the current etc etc..
But I could be wrong…