large live update file

my live update updated yesterday, and I went to run it today and it says I have 175MB to dowload, I already dowloaded a big file..is this normal?

 

 

a little more info: i recently got a new comp ( a week ago) and then downloaded Norton from the site, since I just renewed it in August.  And I had a big download then.  Now live update says it updated last time 24 hours ago, so I went to run live update myself and now it says I have 175MB to download.  I am on a usage limit and don't want to go over, I never had this amount useage until the new computer.  Is this normal?