"If i'm running 5.1, would this number be lower due to additional channels driven?"

Yes, indeed. Note too that the 220W figure is based on 1KHz input (with only 2 channels driven).

Are you on v4 M80s? How far apart are they, how far is your main listening position, how far away are they from the front wall and side walls?

I ask because you can make your soundstage bigger, even with less power, if you have the right version and position them well within the room and with respect to you.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated