I wouldn't worry about it. H/K is notorious for under rating their amps. I have heard an AVR 130 with M60's and it played plenty loud.

How do you have your center channel set? Most around here bump the center setting up a few db to help with the dialogue.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70