Given you had already observed one item break and assuming independent events, the odds of a second break are about 1 in 100... that's not particularly far fetched. A little improbable but definitely not impossible.
From what I remember item breaks lined up pretty well with the expected outcomes, but I haven't had any breaks in about 10 months so I don't have any anecdotal evidence for you. (However, the math from displayed break chances seems to play nicely with skilled gear/support calculations others have done.)
Have you considered adding support gear to your teams? I'm not sure which packs you have but a couple balmungs (giant pack) or midas gloves (heroic 1) can go a long way towards preventing item breaks.
Personally I wouldn't fuss over item quality unless you've got support or you're going for unbreakables, the chances of someone smashing something is just too high when you've got 25 heroes running with 7 gear each.
If you haven't seen it already, this post has a nice breakdown of the odds of breaking something: viewtopic.php?f=6&t=7105
And this post is a great introduction to thinking about building skilled teams/using support in general: viewtopic.php?f=6&t=6237
Anyway, probably not the answer you were looking for but might be worth a read if you're tired of item breaks