True, except that Master Gain is typically a set-and-forget control, 99% of the time being left at the unity gain detent. Adjusting levels during the take would be done with the input channel faders and both the 302 and 442 have nice smooth controls there. It's one of the differences between live sound engineering and location recording - with live sound you ride the master to control the overall system volume the audience is hearing and the channel faders tend to stay set for the balance you're trying to achieve between the instruments, vocals, etc. But in location recording the master is usually set as part of establishing the gain staging between the mixer and the recorder, balancing the mixer's overall gain with the recorder input gain so they're both running at their optimal levels. Once you've achieved that balance, the master stays put and subsequent level adjustments during the take are done with the individual channel faders.

Master Gain
 

Absolutely, Steve! I have moaned to SQN about their 2S and 4S Mini mixers for some time as they have the Master Gain control (used perhaps once or twice a year for location recording) very accessible...bang next to the headphones level control and easily mistaken for it when rummaging for it when the mixer is in its bag around your neck. Whereas the audio return level control - needed each time you connect to a new camcorder - is accessible only with a little tweaker, tilting the mixer up towards the light and squinting. Designers not listening to the guys in the field.

"I was born sneering." Pooh Bah in The Mikado - W.S. Gilbert.