Right. If you enter the print properties from the application with a document open, that controls how that particular document is going to print. If you open the printer properties from the Start Menu, that sets the system defaults.

The interesting part is how it's changing away from the defaults when you open a document. Perhaps in this case, your printing preferences are cleverly getting saved with the document? Have you tried:
- Opening the document,
- Going into printing preferences from the document and changing them to your desires,
- Then Saving The Document?