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
Leverstock Grn 0 Harefield Utd 2 -0.3
Ampthill Town 3 Leverstock Grn 0 -0.2
Hillingdon Boro 4 Tring Athletic 0 +0.1
Stotfold 3 Colney Heath 1 -0.1
Hillingdon Boro 1 Colney Heath 5 +0.1
Biggleswade Utd 1 Hanwell Town 2 +0.0
Oxhey Jets 2 Biggleswade Utd 0 +0.0
Week of 4/20100.0*Average seed
Leverstock Grn 4 Hadley 2 +0.6
Colney Heath 2 Tring Athletic 3 -0.2
AFC Dunstable 6 Leverstock Grn 2 -0.2
Ampthill Town 3 Hertford Town 1 +0.1
Hillingdon Boro 0 Holmer Green 1 +0.1
Week of 4/27100.0*Average seed
Tring Athletic 0 Ampthill Town 2 +0.3
Leverstock Grn 1 St.Margaretsbry 5 -0.1
Points
Chance Will Make Playoffs