Guess,

Something like
6pts for a win over track/distance
4pts for a win over distance
3pts for a win at the track
2pts for other wins.

Lets say a horse has had 10 career starts.
Maximum points available would be 60pts.

Now assume a horse has done the following:
2 wins over distance = 8pts (watch for double counting here - excl track/dist win)
1 win at track/distance = 6pts
1 win at track = 3pts (excl 6pt win)

total points is 17, 17/60 is 28%.
Then have a rule where if the fav's total pts are less than 20% of maximum available - no bet!


Something worth looking into anyway. Save the $160 (use it to punt with) and do some research.