Custom error code range and error rings/Labview 2013 SP1

Hi,

for custom error codes there are these assigned ranges:
-8999 through -8000
5000 through 9999
500,000 through 599,999

If I create a "Error Ring" in Labview 2013 SP1, then I am able to choose from predefined error codes or I can put in some custom error codes. Curious as I was I chose "Labview" from the dropdown menu and looked up some error codes. I noticed that there are some assigned error codes which are in the range of the custom error codes (see attachement) from 538170 to 538193.

Is this a bug or feature? What is the impact if I define custom error codes with identical, already existing error codes?

Regards,

Thomas