"You might want to have another look at it though."

My spread sheet reads like this

All up
307 bets
14.48 units profit (started on the biggest loser day)

$4 & above

65 bets
25 unit lose

Laying the $4 above 1.5 units profit
Backing the Firmers and Drifters is the big loser 26.5 units only two winners in 29 bets

This is opposite to your sample spread sheet where both are in good profit.

I find a good day can be spoilt by a $4 lay getting up late in the day.