Turnip,

When someone asks you the time, do you tell them how to make a clock?

Your heads and tails analogy is very neat but not relevant to racing. If a true even money chance were on offer, the tote would give you about $1.75, the bookies maybe $1.85.

But the real question is, what is an even money chance? Ask 100 different people to rate a race and they'll come up with a dozen different prices for a certain horse. Ask 100 people whether it'll be heads or tails and it is 50/50. Don't attempt to make a complicated situation too simple.

If I get 30% winners and average $4, I don't really care whether my horse is "value" or not. I'm getting 20% POT so why does it matter?