Unfortunately I'm on a business trip and couldn't bring with me the real thing.
I identified together with Joerg Hartenberger, a new set of interrupts not emulated by MAME that happen in the real thing. This is most probably where the error is coming from.
Bottom line, as soon as I can grab my setup back home, I'll test it on the real thing and I'm quite confident it's going to work. If that's the case, before the end of the month all tables for all games can be released...