When people discuss an item not being looted based on the rules defined, this may help.
Recently, Oracle and I were looking at a ring that had LRC 20% on it. The rule that was included was "Lower Reagent Cost >= 15" and the human logic was that it should grab that ring, but it did not.
TM often explains that testing rules should be done using a container with your item examples you want to loot out in the wild and process your rules against that. That is exactly how we solved it and it took more times looting the secure than I remember.
What I did discover, this rule would loot armor really well, but left all jewelry in the container. I had added other jewelry both above and below the threshold of 15% just to see what would happen.
What finally worked was a complex rule made of the individual rules:
Jewelry
Lower Reagent Cost >= 15%
Which looked like:
[Jewelry AND Lower Reagent Cost >= 15% ]
So be willing to test your rules for success.
Gaderian