I bet its like, theres a max iLvl to calculate from, and it just won't calculate the Xs.
you have 1 item equipped, max iLvl is 200, 2 items = 400 iLvl, and then it calculates the avarage you have and gives the points. But, thats just the logical in me thinking.
Nah, in this case the prob was that you got score from cached gear (your cached gear is indeed ready for sunwell), but when "live" took new data from armory, you were wearing only belt, and even xml data for this char had an error at one point, thats why it didn't update your score, which in this case should be 0 ofc I'll fix it so that it doesn't mix cached data with raw data when it encounters an error in xml. This is the first time I saw an error in armory xml btw, so it shouldn't happen again.
btw... did the same with Natorian in my guild... and it did the same for him. I logged off in full gear today but have only left his gloves on...so his actual live and cached should be the same.
Edit: I say this because my gear score was actually scored higher with only 1 peice of gear vs. my full set...
So IMO check Natorian cause that toon has only had 1 peice on all day and was logged off as such.