I'm 100,000% sure you're 90,000% wrong.
Either way, I'm not sure how people can assess the mixes to be "flat" when these are some of the worst sounding bootlegged Beach Boys recordings to surface. Not sure what you have access to, but the stuff we have sounds like total dicks and there are a lot of things I hear that kind of make me think these weren't intended to be final mixes at all.