There is a difference between legal and what you can get away with. Legally you can have more than 6/12 and 8oz... but if the cop chooses to say you are over the limit, it is up to you to prove it is medically necessary in court. So yes, 99 is legal, as long as you're willing to go through defending it in court if you ever have legal issues. 6/12 and 8z is what keeps you from having to deal with that in court (unless you are dealing with a dick cop, which fyi, they can still arrest you for it regardless it may just get tossed later once you get it to a judge).