I am not sure those time frames are really accurate for stages of MLC.
Also, I think that there is absolutely no way of knowing when they actually started to slip into crisis so I don't think there really is any way to determine how far in BD is. Yes, we can see when they started seeming different but it is so subtle and creeps in so slowly that I am not even sure an MLCer in hindsight could pinpoint it exactly. All I know is that my husband has been in crisis for what feels like forever.