Just a word of caution. Sending back your Advanced Replacement from MS without sending back the original has proved to be a huge pain in the rump.
MS understood why I wanted to keep my original and send back the replacement (fully setup vs. losing a day to setup a temp replacement) but executing that in their systems proved to be difficult.
If I had known how challenging and slow it would be, I would have switched over to another laptop and sent the original back so I could do an in-store replacement of the one that doesn't work with the dock since it was easy to reproduce.
Long story short, replacement device #3 is on the FedEx truck to be delivered this morning. Hopefully 3rd time is truly a charm.