All,

I ran a very quick test on the betfair prices from bat over a month.

Using the retirement plan and only betting on favs every race produced a profit.

also

Using the retirement plan and only laying fav on every race produced a profit.

Betting on Fav:
Start of Month : $1000
End of Month : $2473.42

Laying Fav:
Start of Month : $1000
End of Month : $2691.93

My question is why ?

I have my own thoughts ... but interested to see if anyone else has any insights or research in this area ?

Good Luck.