Thank you for your contribution to this thread.
In the case of inter-MSC handover, MSC-A is the switching element. All call control (including CDR and signaling) remains in MSC-A for the entire duration of the connection, this is called the anchor principle, and of course the connection between MSC-A and MSC-B is maintained during this time. After the call is finished, all data related to MS from VLR-A is tranfered to MSC-B by mean of MAP messages. MSC-A cannot be out of the picture.
The LU will be executed only after the end of the call.