Yup, that would be me. I didn't know the difference until now. I didn't see FBA as a different emulator for the same roms, I thought each had their own different romset, with different files. But now I realise FBA is simply running (the equivalent of) a more recent and refined MAME romset, with focus on more recent games, as the MAME version that runs on those systems is an older one. Either way, I noticed differences in the emulation of the same game, so I'll stick with both emulators, each with their own romset.
So maybe my suggestion of adding "umk3" may be an invalid one by now, since the latest MAME romset should regard it as a parent, as much as FBA does.