Font Changes When Saving to RTF

I prefer 11 pt Calibri as my default font. However, I have a boss who wants a certain kind of report in .rtf format, 10 pt Times New Roman. When I save an .rtf file in LibreOffice 4.1 (on Windows 7), the first line changes to 11 pt Calibri and a new blank line of 11 pt Calibri is added to the end of the document. (This last is annoying if my employer or I makes additions later.)

I have solved this by setting WordPad as default for opening .rtf, but I would rather use LO if possible.

Does anyone know anything about this?