Thanks for your answer which is REALLY interesting to me because I'm having serious oil leak trouble (see topic:
http://www.volvoforums.org.uk/showthread.php?t=255742 )
and I actually thought that the metal dipstick I have was a bad one, which explained the weird results I get when checking oil level (see pics).
So maybe I just have a genuine metal version and my engine is just nearly DRY O__O