So if the service was done at a BMW workshop but it was forgotten to be entered in the service booklet, then BMW can look into its history. And if the oil change was made somewhere, you unfortunately have bad cards because you can not find anything. You could read out the service counter with ISTA but that doesn't mean anything if you don't know whether the oil change was made at all, how do you want to know whether it wasn't simply reset or whether a service was carried out in between? Otherwise you could still ask the previous owner if he has any documents.
