How are these numbers calculated?

Big Games

How we did last week and who we should root for this week.   Explain

Week of 8/15100.0*Home Advantage100.0*Average seed
Canterbury 7 West Auckland 1 -11.8
Canterbury 4 West Auckland 0 -2.3
Week of 8/25None
Week of 8/28100.0*Home Advantage100.0*Average seed
Southern 3 Canterbury 5 No
Chance Will Make Playoffs