It has been suggested that the reason movies are being turned down is because the commercials are too loud. I'm calling "Bullocks." I wish a projectionist was in our group to confirm or deny this, but my impression is that the commercials are being played back off a different system than the movie. I'm talking specifically about Pacific's the Grove and Westfield Century City AMC (Los Angeles). For one, the "Pre-Show" is not framed on the screen in the same way. You can tell it shifts when the Trailers/Movie starts. Also - the "Pre-Show" sounds like it is only coming from behind the screen (not 5.1).
What's my point? They have different volume knobs, so don't blame the spots for your loud mixes.