Interesting. I had something similar happen last month when I bought my E39 from the local BMW dealer here in New Mexico. The carfax showed only registration events with no mileage references, except when the car was traded in. The car is a local one owner vehicle originally sold by the same dealer. I prodded the salesman for service records and he finally produced a list from which he read the service performed. He would not let me see the list. He said the forms are not allowed to be read by any third party person. That made me very suspicious they were hiding something, but my PPI came back clean so I went ahead with the purchase. It has bothered me ever since though.
The dealer did give me all the original docs that came with the car. That included the service book, so I have some written service info.
Does anyone here no for sure what the official BMW policy is regarding service records ?