There's no such thing as having to be frame perfect in this game. It not only randomly eats inputs, but it will also buffer inputs so after the player immediately gains control of the skateboarder, the last applicable keypress will be executed. That includes quitting the track, which is vital in this instance as there's unavoidable slowdown with a fresh start of the track when you load up the game, so I basically have to quit then immediately start the track again.
All these runs have been recorded and capped at 30 FPS which seems to actually correct the slowdown somewhat (at the cost of being a bit laggier). In the future I may or may not experiment with just the uncapped framerate of 75 FPS for runs, but it's all so glitchy in all honesty, I prefer the game to run slightly slower so as to mitigate instances of glitchy unpredictable lag. It gives me more reproducible times.