Win 7 Update

Perhaps someone from Norton can clear up my confusion.

 

I have two partititions, one running Win 7 RTM Professional, the other running Win 7 RC Ultra.

 

I downloaded and installed NIS 2009 from the Norton web site into my Win 7 RC partition - it installed 16.7.2.10, and ev erything looked good - no error messages and no problem with advanced scanning.

 

I tried the same for my Win 7 RTM partition (I have sufficient licenses to do both), and it downloaded and installed 16.5 with the accompanying advanced scanning error.

 

Does Norton detect the O/S before downloading the setup file and is the 16.7.2.10 ok for the release candidate but not for the relase to manufacturers version?