Currently, the file was converted over to 2010 as an "xlsm" file. I did convert it following the link that you attached. But if I go to File/Check for Issues, this is where it tells me there is a compatibility issue with pivot tables. Should I just ignore this if I used the "convert" option to changeover my file?? So what is it now....
It sounds like it is trying to maintain the previous version format. Changing the extension doesn't guarantee the conversion to the new format.
In the following link see the section "Convert a workbook to the Excel 2010 file format" (also applies for 2013.)
Since you indicate Macros exist in these workbooks, be careful and maintain a separate copy. I have not tested what happens to macros when converting files.