Well that just means there are 2 entries for that IP address. If you search for "NET-67-228-0-0-1" you will get who it's assigned to, and a search of "NET-67-0-0-0-0" shows the upstream delegator. The tool is *mostly* for whois... but yeah... will work for IP addresses too, but if it returns multiple results, you would need to then search for which you want to get the detailed info.