Fair enough then, I guess I missed that somewhere along the line. My mistake.
Looking at descriptions, I have to agree that Melee would probably have been evaluated at E10+, but under that assumption I don't see why Brawl would get a T rating instead. I'm not convinced Turtlekid's two examples would be enough to bump it up.
I can't help but wonder if precedent plays some role in the rating of games within a series. I wouldn't imagine it would, and that each game is 'tested' individually and impartially, but I admittedly can offer nothing but unsubstantiated conjecture.