George:  I had mentioned the same point in another post about the CM-30.
   http://www.synthzone.com/ubbs/Forum37/HTML/016357-2.html  Peavey used to play the extact same game (listing power ratings at 2 OHM instead of 8).   Looking at the SRM150 specs they list the amp at 100 watts continuous, 150 peak.  The speaker is listed at 8 ohms but they don't say they are driving it at 8, they could be driving it at 2.  Hearing both the Roland and the Mackie I agree that the 37 watt at 8 ohms is probably more on target.  I also have an older TOA that is 25 watts.  The Mackie is louder but not 4X more.  
It's a shame that Mackie thinks it gives them an advantage in the market place by playing games with specs.