Easier to get an SSS rank on DMD and SOS?! Come on now. Avoiding a Witch and Tyrant at the same time is not easy. It's easy to get double S ranks, not triple. It's easier to get a D by just letting yourself die a couple of times and abusing items.
So... Is it me, or is the final score not determined from an average of ranks, but from the total actual scores? I mean, a 1M-style-point SSS would be worth considerably more than a 100K-style-point SSS, despite both being the same rank? It certainly would explain that SSS-C-D-0-3 thing I saw still getting SSS, since the style points were in the millions. Someone post that vid again, if you know where it is.