Partypooper has said all that needs to be said.

Horses can easily be backed at TF bookmaker odds with a minimum odds proviso.

Betting exchanges are also a reality.

As a general comment if I was forced to bet into markets consistently around 120% I wouldn't waste my time. There would be far better things to do.

TF bookmaker odds in Melbourne and Sydney on Saturdays for most races are well below 120%. There are standard exceptions, like races full of unraced 2YOs or lightly raced horses resuming from a spell. But I don't touch those races for Specials.