Don't know if this was intentional or not, but when filtering with the "Show only Completed Series" in Series Info, the completed series are those with (Complete) in the Status column (as mentioned here http://www.mangaupdates.com/showtopic.php?tid=246).

However, if I'm not mistaken, the "Status" heading is the Status of the series released in Japan... (at least that's what I had intended it to be when I first suggested that heading ages ago...). Thus, while the series may be completed releasing from the Japanese publisher, it may not necessarily be completed in terms of scanlations.

An Example (first one that shows up on the "Completed Series" filtered list)... http://www.mangaupdates.com/series.html?id=1687
Latest Release(s)
Release: v.1 c.1 by Pouet Manga Scanlation
Status: 10 Volumes (complete)

If this was intended, pretend I never said anything and lock this topic. If my logic seems to make some sense, maybe the "Completed Series" shouldn't be filtered base on the Status? Or a seperated "Completely Scanlated" series filter could possibly be implemented? (although a list version of it does exist here http://www.mangaupdates.com/showtopic.php?tid=76)

So, really, all this boils down to is the definition of "complete"... and I'm mildly entertained by how my li'l suggestion so long ago has progressed so far.

Correct, it is intended to represent the manga status in Japan.

Someone suggested a "Completely Scanlated" feature, but at the moment it is not too high up on my list of things to do.