Dear @ericsch : You don't have to worry about, are safe down there.
In the other side the tonearm effective mass spec is only that but you or any one else know the tonearm counterweigth position when Technics achieve those 12grs and the compliance never is exactly as those numbers said.
You already made your job that confirms you are ok, no problem between that tonearm/cartridge combination. So, stay calm.
Only as an example about: the Ortofon MC 2000 LOMC cartridge was measured under review with around 35 cu and its weigth is 11 grs. and was mounted in the Technics SP10 MK2 and top Technics tonearm and the measured resonance frequency beteen the cartridge/tonearm was around 5hz and wonder what?:
that combination had no single issue to track with excellent quality performance the Telarc 1812 LP and other tortuose tests LP.
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.