This applies to all the streams: Only the final (oooo) out of each stream is an audible 1/6 when slowed down. The preceding sounds, which would otherwise be 1 or 2 1/4th triplets, are accentuated in a "violent" manner and drag into each other as if they were winding up to a punch. As such, representing them with 1/6ths helps express them better and distinguish the sounds from the rest of the stream. It also keeps the difficulty on par with the song's tone.
Imo not including them drastically diminishes the fun factor