Richard, I understand that if I take out a PRS or MCPS license to perform or record a song, I must be faithful to the original.

But what if I want to make an adaptation, and become potentially co-owner of the copyright? Do I need permission to effect the changes I want? What if I take out an MCPS license, record my own arrangement and register it with MCPS, and simply state on the sleeve "XXXXXX/Arr myself"?