During my time Sinbad, a change to the Kahu system was contemplated. We went so far as to discuss it with the Kiwi pilots and engineers at squadron level.
The change never happened probably for something as prosaic as having too many A13 masks in stock.
Personally, once I learnt the A4 cough, and developed the yawn and pop on the walk in to the hangar, I was never bothered by the LOX under constant flow. Only problem was the little oxy burn beside my nose while at sea (with beard to save water).