Recall this topic in which I said that GBAFE is limited to 8 sounds per song. That limit can now be increased to 12.
This seems to work without hitch so far. You can turn these up to 0x0C (12!) before the game starts having serious performance issues/crashes.
This patch will also allow the games to read up to 16 tracks for BGM and map songs. Keep in mind that the 12-sound limit still applies.
1/5/17: I updated the links in this topic as the dreaded Dropbox update destroyed them.