I've seen that the in-game timer doesn't count lost frames, and it might correlate with the olive roll timer. but it never lags for me in the minigame so i have no way of testing it.
I believe oliveroll% is a good idea and entry point for future speedrunners of this game. after the defeat of the bug gym, it opens up a new harder olive roll to challenge players to get the olive in the basket as fast as they can, offering rewards on milestones they reach. after 30 minutes of trying, I got a highscore of 00:15.33, with the last prize being below 2:30.00.
the goal of oliveroll% is to get the finish screen to trigger. in my attempt, I pushed the olive over the wall and got it to push against the side of the basket far enough in to count as a goal. I'm sure I'll discover other exploits in the meantime.
The game already records your time, so you can speedrun this on a switch without having to insert a timer over the top in post. all in all, I do think this is a really good category to have, and I've yet to figure out some rules.