The rules are these as outlined:
Divide your bank by 9 to decide your first bet amount.
If the horse is unplaced divide the bank again by 9 for the
next bet and continue dividing the bank by 9 until a selection
runs a place.
Whenever a selection runs a place your next bet is the remaining
bank divided by 5.
If that selection runs a place the next bet is again the bank
divided by 5 (20%) and continues at that level until a selection
If a selection loses, the next bet is the remaining bank divided
If that loses the next bet is the remaining bank divided by
9 and stays at that level until a selection runs a place again
(and sequence then repeats).
(In other words, every time a selection runs a place the next
bet is the bank divided by 5 - there's a "shoulder"
bet of divided by 7 and then return to the divided by 9 amount).
This works best where your place average result is 60% plus
staking plan can make up for plainly poor selections.