ParentsB2 extension approved

I just the ins website and it shows my parents extension has been approved. I have not received the approval letter yet.

I have one question. The customs only gave my parents 3 month stay when they first got here. I was told they can only get 3 month extension if the customs gave them 3 months stay.I applied for 6 month anyway. I was wondering if anyone has their parents visa extented recently and how many months in the new visa

Thank you