I don't think the 4% break chance is actually working at 4%. Several of us in vent have noticed an average of 3 or 4 items breaking per round. Once is a fluke. Twice, an anomaly. But when it's the AVERAGE, it's a pattern. This should be looked at. I hope you're saving breakage stats in the database. If you are, you should probably see more than 4% breakage if you take a look.
Even with full 8 inventory slots, at 4% breakage, you should only see an item break every 3 rounds or so.
Or is the 4% breakage 4% per minute, rather than per round?