I would discourage an arbitrarily established value. Failing to deal with a value below '100' might prove to be determental.
On the other hand, unwisely dispensing resources to countermeasure a low rating could prove equally bad.
Keep in mind that the
FMEA is a LIVING DOCUMENT. This means it must be revisited from time to time. As such, you might find that an RPN for an item that was low because of a false expectation proves to be high. The reverse is also true. Still, as the process or system changes, the RPN could toggle back and forth.
So when do you react? Well, what is a manageable risk? Keep in mind that the organization for the most part is the AUTHORITY on the process or design. You make the decision as to what is a high or low risk (please pay attention to regulatory requirement, ie Essential Requirements which govern your actions). Being the authority on the product/process, the experts, and having knowledge of your manageable resources, you pick your own battles.
Another not so scientific method, but perhaps better than arbitrarily established RPNs, is to use the 80/20 principle. Use Pareto analysis to establish your priorities and address the "vital few" as your resources permit. Use Corrective/Preventive Actions. As you periodically do your review the FMEA, update your RPNS,reprioritize, and repeat the process.
Just another opinion.
Regards,
Kevin