I have noticed that pressure cookers are often not used efficiently. Its quite common to run them on high flame or heat throughout. This is wasteful. Once the water starts boiling in that high pressure, the interiors are a constant pressure constant pressure system. The heat needed to sustain it is surprisingly and significantly lower, just need to cover for the losses. All that extra heat is just heating your kitchen. This is relevant to the discussion because whistle count is strongly dependent on the flame: too high and you would need more whistles, rather counterintuitive. A timer that's set off after the first whistle would be closer to what one needs. Finally too cook fast, set the flame high till the first whistle and then let it simmer