Ah, so it actually changes Arrange Mode's difficulty to be replaced with Original Mode, but doesn't change the "physics" linked to the Simon sprite.
Hmm. I looked up codes to change this, and I didn't find any, so I can only imagine this would need to be investigated within the game's code.
Unfortunately, this is an old niche game, so I'm probably the only one who cares enough about this problem, but I lack the technical knowhow to even handle it...phooey! ;_;