Hi,
I was asked to look into this, though my perspective is somewhat dated on these matters. Timing stuff is fairly timeless (haha) and there's a few big issues with this set that I am surprised (and slightly horrified) were not adequately addressed before it hit Ranked.
To start, 3/16 is not a common measure, nor is it readily reproducible by the human ear. There is a distinct reason as to why 1/16 snap is marked in the editor with a violent red, non-toggleable "YOU SHOULD NOT USE THIS FOR ANYTHING EVER" snap because it is essentially unnecessary in 99.999% of all use cases, and is historically only really used to apply accurate timing to syncopated or non-measure additional sounds in certain sets.
Ishukan Communication is an fairly simple and straightforward swing style song. Common sense dictates that 1/6 snap is indeed the standard use case for this, and with no musical variation to support the 3/16 argument currently in play (the song is not experimental, nor is it heavily syncopated, nor does it possess non-snapped or non-aligned sounds). Indeed, snapping the map to 1/6 as-is from a fresh download without touching timing produces a result that sounds immediately more correct than its current state. It also, as ARGENTINE DREAM states, shaves more than a 1.3 stars off the map's overall difficulty as calculated by the score processor.
That is hugely significant.
Player feedback readily reflects (from the disqus comments) that the map is considered widely too easy for the sort of SR it gives, and it is a more than plausible explanation that incorrect insistence on 3/16 is responsible for this. 3/16 may produce a result that is playable, but it is an incorrect result. This is compounded significantly by the 'complex' BPM timing (107.96) for reasons that I will explain below.
A track with 108 bpm has 555.556ms for each beat in the track. A track with 107.96 bpm has 555.761ms for each beat in the track. Scaling this down to 1/16 snap, we see that each snapped point represents a 34.7225ms interval at 108 bpm, and a 34.735ms difference at 107.96. Conversely, the interval at 1/6 is 92.60 ms at 108bpm, and 92.63 at 107.96 bpm. The differences seem infinitesimal, but when you consider that an incorrectly timed set using an "approximated" bpm (which complex or decimal place bpms are by their nature), this introduces a constant drift of essentially 30~ microseconds which elapses throughout the entire duration of the track, resulting in extremely subtle and often very frustrating drifts in accuracy which worsen significantly towards the end of the track, to the order of a 2.6ms total drift as felt by the player. At the later end of the track, using a 1/16 snap exposes an inaccuracy window that is almost 10% of the given division for that particular beat. Completely unacceptable.
That is but one reason why we do not use 1/16 anything.
From experience, there are a few explanations as to why a track like Ishukan Communication could be subject to this sort of drift. A distinct possibility is guff with the sampling rate when transcoding - this is unlikely in modern builds of many common encoders however. What I personally suspect is poor production given that this is a TV Size cut - there are perhaps very slightly uneven cuts between verses and the main chorus (to the order of less than a few milliseconds of difference between them) which gradually add up towards the end of the track to produce the difference that is cited as the reason for using an approximated complex bpm. Fixing this is as simple as resetting the bpm to 108 at the beginning of every major cut (ie from verse to verse or verse to chorus), likely only needed at the latter end of the track where it begins to unravel itself.
Timers with more experience with complex bpm tracks will likely have more useful suggestions on how to fix this particular issue, but there you go.
More importantly, the issues with this set were obviously not resolved sufficiently post disqualification. I wouldn't have been summoned in if they were.