How are these numbers calculated?

Big Games

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

Week of 7/30100.0*Chance in playoffs100.0*Average seed
Dunedin 5 Canterbury 7 +10.4
+0.2
Dunedin 4 Canterbury 7 +9.6
+0.2
Southern 2 Botany 3 -4.4
-0.2
Week of 8/6100.0*Chance in playoffs100.0*Average seed
West Auckland 5 Southern 3 -41.5
-0.4
Canterbury 13 Botany 4 +26.7
+0.4
West Auckland 6 Southern 3 -26.2
-0.3
Canterbury 6 Botany 1 +20.2
+0.2
Week of 8/13100.0*Chance in playoffs100.0*Average seed
Dunedin 2 West Auckland 0 In
+0.8
Dunedin 2 West Auckland 8 -20.2
-0.2
Points
Chance Will Make Playoffs