You are spot on Onebet.
Unless you back double figure odds horses you will be behind the eight ball betting on the tote regardless of whether you bet win or place. However, as pointed out in your example, the effect of rounding is more drastic the shorter the price and also the weight of popular money has a more drastic effect on the shorties on the place tote.
You could open an internet betting account with a bookie and bet for as little as $5 per wager and get a lot better deal than you currently do.