It is apparently possible to assign 99 helpful and 1 correct answers to a thread, which was obviously configured during a recent forum maintenance. Yet more new forum features. However the exact number wasn't mentioned. And I guess that's quite a change from the previous limit of 3, or 5 in the previous system, and probably worth mentioning.
Yes that was done as part of the recent 'patch'.
Not quite sure of the exact reasoning, though I think it's because of some complaints about it having gone down from 5 to 3 with the upgrade, as well as the obvious fact that some OP's (especially newbies) are very quick to mark initial responses as helpful, just because they've had some response, and then the found they couldn't reward subsequent really helpful answers, especially on longer running discussions.
It's probably also something to do with the MOSC forums coming onto the Jive platform and their requirements... though I'm not particularly familiar with what goes on over there (I have access, though I've always hung around the public forums mainly )