To clear up some confusion above.
The data pulled from the GDS only gives access to confirmed seats. Those not confirmed won’t appear. The data is way too patchy to confirm numbers until the flight has closed, it varies across all carriers and really depends on the systems they use. Those Virgin Brisbane numbers above are not accurate, they will likely depart with 90-100%. The Virgin data is still debatable post departure, gets messy with a whole heap of complex other parts around seat blocking and awards, GDS would often under read.
Rex figures are concrete once a flight has closed only, very basic carrier with very basic systems which is why you can get a accurate reading post departure. Anything prior your wasting your time reading into anything.