Anyone know if the serial numbers are in sequential order? I did an in store exchange when I first purchased my Surface Pro 2 and the replacement had a higher serial number. I also received 2 advanced replacements later one and both of those had lower replacement numbers. I did another in store exchange and it had a higher serial number than my 2nd unit. I just did another in store exchange but this one has a lower serial number even lower than one of the advanced exchange units, but it has a 4300U chip. First 2 started with 03, 3rd started with 003, 4th started with 005, 5th started with 03 again, and the current one starts with 004. If serial numbers are in sequential order my current unit should start with 04 no 004. The 3rd and 4th units were advanced replacement units which means they were refurbished which explain the number numbers, but my current unit was a brand new retail box unit from a MS store that I got as an exchange.