On incoming dispatch advice lines, you get both these options to receive as we do have some parts that are serial tracked.

If we use the 2nd option to receive, the system does not display the original lot# however the 1st option does.  I have searched to try and determine why.  Am I misinterpreting the RMB label?  

When it is a serialized part it does not populate the lot# but does the serial number. Can anyone help explain this?