Don’t know about other models. I owned MC2250, rated 250 wpc, factory measured 305 wpc. McIntosh are conservatively rated.
For inefficient speakers, My MC2250 was dead quiet, never knew it was on, had to remember to turn it off. Nothing right or wrong about it, just invisibly did it’s job. Factory told me, leave it at max volume, simply on/off, use preamp conservatively.
I went back to efficient speakers, back to tubes, prefer them, sold it eBay, no meters, got less money, and less watchers, that's my reference to meters.