firstly please allow me to apologise on the brodsters behalf for ignoring this portion of your question.
not sure this will apply to the brodsters betting (i imagine anything he touches would surely shorten too much to represent value a day or so later) but say you were betting to win 1000 then knowing the deduction % would allow you get some more on (subject to value) to retain the opportunity to win 1000.
that was on rising stars final night, he had finished a distant 4th in his heat which was by far the fastest heat. The first 3 in his heat were the first 3 home in the final. The other heat winner was tuapeka knight and he missed the final also.