Strange, because I sure did downgrade to 9.2 with supermysterychunkhax on a New3DS, on 10.7, using PlaiSysUpdater, setup RedNAND, and am currently in the process of injecting FBI. (At Step 4 of Plailect Guide)I can confirm that SVchax/Memchunkhax 2.1 DEFINITELY does NOT work with the current version of the exploit of this game on a New 3DS. No way to downgrade yet with this explot.
Which makes your confirmation incorrect.