Although this will work, keep in mind that the "Write to Spreadsheet VI" is in the VI library of LabVIEW, and any other program that you write will contain the modified version of this VI. Therefore, I would *strongly* suggest that you copy the Write to Spreadsheet file VI to another filename, modify it, and then use that file instead. This will prevent a lot of headaches, should you use the original VI in other programs.
Mark