NIS 2012 falsely showing system status as "secure"

I have a netbook which I only use about once every 2 weeks. It has NIS 2012 installed. When I login after a 2-week absence, my system status shows as green "secure", even though, when I check Live Update, there are usually over 10 updates waiting to be installed. Surely, it should not be telling me all is OK when it clearly isn't? Of course, running Live Update is the first thing I do once logged in, but even so.......