My DS will also be at 2nd session... I don't know that it gives them better odds, but I do know if they are accepted it means they have met the first basic requirements to become an official candidate. Did he get that letter yet?
For about 95% of those attending, it means absolutely nothing with regards to the actual admissions process. For the 5% that get high remarks from the NASS detail, it will help them a little (emphasis on "a little").
He has received a letter with his candidate number along with a username and password for access to the CIS system. We were unable to access the CIS originally but using a link given on another post here we were able to acces the CIS.