Definition of music power!
Back to the subject... I have found a definition in Randy Slone's amp book:
Originally from R. Slone
Music Power - An ilegitimate term used to describe the output power of an audio amplifier. In reality, it is a schrewd way of squaring peak output values instead of RMS values when calculating power, and amounts to nothing more than a marketing gimmick to promote sales.
I guess the only reason you would need this with your speaker specs is when your amp is rated in "music power"
(I hope your amp isn't rated in music power!!)