I don't have any experience with iBackup

so can't comment on what that may be doing to your documents.

To change your default line spacing in Word 2007, you may have to modify the default paragraph style instead of just clicking the Default button in the paragraph dialog box. Have you checked the style to see if your spacing was in fact changed?

Yes, opening a document on a different machine with a different printer driver can change the layout of your document. A different printer driver can change margins and tabs and add additional pages. This may or may not be your problem -- it's only a suggestion for troubleshooting purposes. Windows comes with many printer drivers in the Add Printer applet in Control Panel. You can try changing your printer to the printer the recipient is using. Again, the printer does not have to be physically installed on your machine.

The recipient of your files should be able to open your documents without any problems when you save in 97-2003 format. You downloading the 2007 Viewer is not going to help the recipient. The recipient would need to download the free compatibility pack from the Microsoft site to open and edit Word 2007 documents in the .docx format.

As for your tabs in your column examples, what are your actual tab settings? You are tabbing twice. Is your first tab setting aligned with the longest text, i.e., after Performance I.Q., so your numbers align properly?