One thing perhaps is whatever the deal was for how the networks deal with the 36 station per multiplex limitation discussed back here Digital Radio - Technical - #1403 by RFBurns
9A is at 33 stations, but SEN are quite overrepresented despite not having bought any excess capacity, having 8 stations in the combined SEN/3MP space, which is the most that’s possible for all stations to have equal access.
Math and references to capacity units...
So this is annoying to calculate with the difference between “bit rate” and actual capacity. Stations got allocated 1/9th of the multiplex, which is 128kbps at the typical EEP-3A, or 96CU.
When the excess capacity was auctioned this was in 32kbps chunks, or 24CU.
If owning access to 24CU gets you 1 station, the math works perfectly - SEN/3MP have 192CU / 24 = 8 and 36 * 24CU = 864CU, which is the total capacity of a multiplex.
RSN and Nova would be entitled to another station, as well as one more community station to max out at the 36.
On 9B the Triple M redirect puts SCA over their maximum if the above was the case, but maybe they are free to do that until another network decides they want to use it, 9B is only 30 stations inclusive.