The second script is the content of the file /etc/sudoers.d/bluetooth-pan.sh you should create and you should run update-sudoers for it to take effect such that sudo bluetooth-pan.sh work.

It is strange that the script doesnt work under root, probably wrong path. You may want to check the correct path of the file, i.e.

You may refer to latest version of the script for detail procedures. Tell me again what I missed.