The Scene phrasing time is not reducing to 0 as claimed in your corona 15 update video. What is the exact reason. its a slow camera dolly shot with only water animation. no major animation.
As a note the video doesn’t claim reparsing later frames always reduces to zero - it depends on what is changing. If there is only a camera movement, then later reparsing can reduce to zero, but you note here that the water is also animated - is that an animated displacement? Or a physics simulation? Since that changes each frame some reparsing will need to be done. Does the reparsing time change at all from the first frame?