Ya, I suppose that's what this is.
I'm using a non-merged ROM set, but when I select only 1 MAME game and I let the export wizard run, when I check the "Android Export" folder after a minute or so I'll see 10 different ROM's in that folder. I shouldn't be seeing 10+ ROMs in that folder (which keeps growing) I don't think there'd be that many dependencies for 1 game and sometimes there won't be any dependencies at all I'd imagine. If you can think of a game that doesn't have any dependencies (I'm sure there's got to be many), we can run the wizard to test it out, but I fear by default even if you select a ROM without any dependencies, LB will still copy over every MAME ROM, which in my case would be 109 GB when all I wanted was to copy over 50 titles.
On another note, I tested this export function on Sega titles by selecting 4 and just the 4 titles transfer, so this is definitely a MAME transfer issue which sucks ;(