i'd be careful with trusting those statements. coffee has very little experience at lower stakes, to my knowledge he started extensively working with analysis tools when he was already playing 100s, so his recommendations are probably loose assumptions.
i have a 12k tournament database at 15s and 30s. i analyzed my expectation when flatting a pfr between 20 and 25bb with marginal hands as well as 3betting them. the analysis gave me pretty marginal results for the bottom of my ranges, even worse than -100bb/100 for the cutoff hands, albeit with a low sample.
the crucial point is: i played 47/29 over that sample from the BB. i have reason to believe that i might be able to add some marginal +EV 3bets to this range, but it is by no means secure to say that playing more hands improves your expectation.
i would go as far as betting against coffee if he decided to play 15s and had to show a profit with the bottom of his range if he is forced to have 60 vpip from the BB, assuming he game selects well and not intentionally plays against regs.
of course he can go ahead and claim that i just suck postflop, that is up for debate, but then again most of us lower stakes regulars are not playing perfectly postflop