That's not as unreasonable or silly a question as it sounds, we've just had a lot of time to come up with an answer. Maybe it's time for a MARP FAQ...(posted 9479 days ago)Every time the latest beta changes, new bugs can be introduced into a game. Sometimes it has affected entire groups of games using similar hardware. Also, the MAME developers adjust the format of the recordings often so to play back recordings made on some beta versions you may have to use the same beta. Many of us are using final versions of .34 & .35 where possible to reduce the amount of chaos.
MAME .34 got used for the second tournament because of a nasty feature introduced in .35 that makes cheating much more powerful. The problem is still in the latest betas.