There is a missmatch of Properties in reading/writing RTF files with included
grafics.
Scenary: Open a new Writer-Dokument (*.odt). Include a grafic (i.e. a
picture-file  *.jpg -> insert - Picture - from file). Sorry, I do not have a
english version, I work with a German Version. So I do not know, if the
menu-items are correct. I will add the German items in brackets).
Now place the graphic in the document, use the mouse for positioning and select
anchor = page. Select the graphic, open the properties-dialog, select "type"
("Typ" Reiter). Anchor should mark at "page" ("An der Seite"), in section "size"
the option ("Abgleich") should be marked, in section "position" the last
Listboxes are marked "hole Page" ("gesamte Seite"). 
Now save the document as *.rtf, close the document.
Now open the stored rtf-Document in OOo Writer, the graphic is not at the same
position as prior. Select the graphic, open the properties-dialog, select "type". 
All properties are the same only in section "position" the referenz-point has
changed to "pagetext-area" ("Seitentextbereich"), which explains the different
Position. 

So, if you do now the same procedure again, but select during the first step
immediatly the referenz-point "pagetext-area" ("Seitentextbereich"), store the
document afterwards as rtf-file, open it again, the graphic is still displaced. 
Now the property "referenz-point" has changed to "hole page" ("Gesamte Seite"),
which explains the displace.

I believe, that internal the properties are missmatched and the attachment to
variables is wrong. 
RTF-export/Import with graphics is actual not useable.