OK, I was wrong...
I am not sure what happened when I compared those two branches because the code is nearly identical in the places where it's important that it be...
I tried "cherry-picking" (ie what one would normally do to backport) on my copy of FreePBX repository and it seems to have applied cleanly...
Josh, let me know if you are willing to wait a little to see if FreePBX 13 becomes stable very soon...
If you are not then I will add a comment to my pull request to ask Andrew if he would be willing to backport this to FreePBX 12...
Have a nice day!
Nick