Trying to find profit from Fav. 'in the numbers' alone without hindsight is of course impossible [a lot of punters still try], but as Party pointed out profit is possible, if you can find an edge and somehow he obviously has.

Some simple examples of creating an edge that would increase that overall Fav.30% SR average would be to remove from the stats. [a no bet fav.] all Favourites carrying over 57kg., or perhaps ignoring all Fav. in races over 2200m or less than 1100m., F&M and Cup races come to mind too as races with poor Fav. SR's that could be excluded as no bets [on Fav.].

Removing any of the above races will improve the 30% SR and removing all of the above would improve things even more.