If you're just opening an XML file in Excel, I've found that Excel doesn't always understand the organization of the file the way you want it to. When going from XML to Excel and back I almost always use Python. I have an example here
. It should be enough to get you started if you hsve some basic programming knowledge.
The problem (and strength) of XML is that you can structure it to fit your needs. This leads to everyone using a different structure though which causes problems like the one you're seeing.