Re: equality: can anyone explain this?
Sometimes, the tours use a different distribution system for prize money. For example, at one of the Spring US Hard Court Tier I events, the women's champion earned more than the men's champion because the women had a lesser proportion going to early-round losers. So while the overall prize money pot is the same (say, 4.5 million USD), they have independent control over how that is distributed among round-finishers.
In this case, I don't rightly know. But there's probably a good reason.