How are these numbers calculated?

Big Games

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

Week of 4/8100.0*Average seed
Slimbridge 2 Bideford 0 +0.5
Yate Town 3 North Leigh 2 -0.2
Barnstaple Town 2 AFC Totton 1 +0.1
North Leigh 2 Yate Town 1 +0.1
Week of 4/15100.0*Average seed
Winchester City 0 AFC Totton 1 -0.4
Wantage Town 2 Slimbridge 0 -0.3
Wimborne Town 0 Yate Town 3 -0.3
Slimbridge 1 Shortwood United 2 -0.2
AFC Totton 4 Bishop's Cleeve 0 -0.1
Week of 4/22100.0*Average seed
Wimborne Town 3 Slimbridge 1 -0.1
AFC Totton 2 Evesham United 4 +0.0
Points
Chance Will Win Championship