You can't compare "FATAL" with a value of -1 to 4. It doesn't work.
Here's your code:
The proposed change, which I have had to make in order for your code to work properly, is as follows:
Sure I could specify numeric values in the LogBox configuration, however that is a workaround that should not be required, and if it were to be required, it should be documented as such, since your documentation clearly states we can use textual values for log level representation in the configuration.
You could improve this by removing the type="numeric" colddoc attribute, and add a isNumeric() check to the arguments.level parameter, so that this function would support either text or numeric representation. That would be most excellent.