Expired Domain Finder

Hi,
i`am new to scrapebox and need some help...

i try to find good expired domains with the expired domain finder plugin.
So when i run this it find some domains, but these domains are only not online but registered.

When i expored this list and run the who is addon it says domains are available, 
a whois request on services in browsers tell me "not available".

So from where get Scrapebox this information, and how often it will be updatet?