Regrettably, yes! Cell balancing is a good example. As far as I'm aware, BMW simply does not refer to it in any of their customer documentation. David Bricknell apparently had access to technical resources within BMW, and he (for example) says that cell balancing may happen at either the module or the pack level - but he doesn't say which. That's significant, because the former is 8 times more effective than the latter. Which is it? All we can do is guess.
Another example: the charging rules that the car uses whenever it is plugged in. We know (from observation) that there are at least two circumstances in which the car will ignore any timed charging schedule that the owner sets, and will simply start charging immediately. But BMW doesn't tell the car's owner anything about that. All we can do is observe what the car actually does, and try to figure it out from there.