How are these numbers calculated?

Big Games

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

Week of 4/13100.0*Average seed
Stotfold 2 St.Margaretsbry 3 +0.2
St.Margaretsbry 1 Ampthill Town 4 -0.1
Biggleswade Utd 1 Hanwell Town 2 -0.0
Week of 4/20100.0*Average seed
Hanwell Town 0 Harefield Utd 1 +0.1
Berkhamsted 2 St.Margaretsbry 4 +0.1
Week of 4/27None
Points
Chance Will Make Playoffs