Well, where do I begin? Lets start with the data in the file. Most employers don't appreciate cost and revenue data being posted openly to the Web. You may want to find another way to answer questions about the problem you're having.

Your file has 28 different worksheets according to the version of OpenOffice (2.2.1) that I'm running. There's a side-by-side display set up for two of the worksheets (or two worksheet sections at least) in the default view that opens. There's a lot of formatting in pretty much every sheet. I was prompted upon opening it about whether or not I wanted to allow macros to run. In short, it's a quite complex file. I'm not shocked that a free third-party library doesn't quite read it properly, even though the one in question does really well on most Excel files.

You might need to export some data before working with it. If you can offer, this file might be a good stress test for further work with whatever Excel-reading libraries (such as but not limited to Spreadsheet::ParseExcel) are available. As I said before, it would be good to get clearance for sharing it if you must.