In ,
Oppie had this to say:

Can you tell me what information OE uses to calculate the 'Size' of
the message? I would like to see if the message size discrepancy with
teranews can still be fixed. Until then, I'm going to use message
lines as an indicator of message size.

TIA - Oppie

That'd be better directed towards Steve. My understanding is that it's a
calculation of the message itself and any attachments but that's just, well,
wrong... I'm guessing there is far more to it as it may even be telling you
the size it will take on disk for instance. If you've ever been bored (it
happens to me a lot so I'm guessing you might have been as well) you'll find
emails with a 12k attachment, a few k of text, and a dozen lines of headers
and OE will claim it's 35 kb in size. So, how it reaches that figure is
beyond me.

I don't know what server software is being used by the NNTP server you speak
of but it could be a bug involved in that easily enough. I did a quick check
on LocalNet's NNTP service and SpamCop's and didn't find any differences.
The sizes show up (with the size column) here without any problems and
appears to be generally correct.

--
Galen - MS MVP - Windows (Shell/User & IE)
http://dts-l.org/
http://kgiii.info/

"At present I am, as you know, fairly busy, but I propose to devote my
declining years to the composition of a textbook which shall focus the
whole art of detection into one volume." - Sherlock Holmes