In the past they have updated the available tracks when there is a batch of them to add, rather than keeping up with them individually. As you point out, they now have a batch, so hopefully they will update soon. Being 8-12 tracks behind the releases is very common, as it isn’t something that automatically gets added on Roll20 when TTA adds something new (the same also holds true for Incompetech tracks). Also, updates of almost any type usually are pushed on Tuesdays. You can watch for the patch notes in the announcement forum, they will mention if they update the available audio.