I only bet in handicaps
My average winning sp equates to 6/1
I never bet ew.

My level stake win is a % of my Bank
The Bank/ stake ratio allows a significant losing run
To bet each way , using my staking method , would mean either halving my stake
or doubling my stake.
My records show that more profit is made by putting the whole stake as a win, rather than half to win , half to place.
It follows that if I was to bet full stake win and full stake place, I of course would still make more money by having 2x level stake to win only.

And still hardly anyone contemplates a win/place bet as other than an equal stakes bet.