Does the excel batch upload template no longer need the node type?

I noted the other day that I was doing an excel batch upload in the test environment for a list viewpoint and accidently left off the node type (only one node type in this flat list viewpoint). When loaded it still uploaded successfully and it appended the node type column and populated the node type at the end of the workbook tab. Is this new? Can I find out further information on how this works, where it works and does not work etc?