Enjay, the default target is always 40 after you win and back in profit?
I use a similar method, default target is let's say 25, PLUS if win and paid under, the target is 25, plus the difference between the actual return and expected return, = new target.
That way it does not have to "talk" to the bank amount.

So if i bet 10 units, and price was 5, but got paid on 4.50, then my new target would be 25 plus 5, (30)
If i got paid 5.00 or over, then yeah, i go back to my default, 25, in your case 40

Yeah ?