shouldn't the bottom line be:
if you consistently meet or beat your deadlines when the music is cranked, crank on. if listening to music negatively impacts your productivity, then no music for you, bunky.
is the manager's goal to set one-size-fits-all policies? or embrace the diversity of the programmer pool for the benefit of the company?
just wondering.
i usually have music on, and find that the right music will support proposal writing, coding, debugging, whatever. if you can't listen and work at the same time, don't.